- Pitcher Plant Propagation: How To Propagate A Pitcher Plant
- Pitcher Plant Seeds
- Pitcher Plant Cuttings
- Sarracenia (Pitcher Plant or Trumpet Pitcher)
- Pitcher Plant Care Guide
- How to Care for a Pitcher Plant Summary
- Pitcher Plant Problems
- Community Comments
- How Do Carnivorous Plants Reproduce?
- The Fascinating Difference
- Life Cycle and Seeds
- Vegetative Reproduction
Pitcher Plant Propagation: How To Propagate A Pitcher Plant
If you’re a fan of the carnivorous pitcher plant, you’ll eventually want to propagate some of your specimens to add to your collection. These plants may look exotic, but propagating pitcher plants is no harder than propagating any other plant. Pitcher plant propagation can be done in a number of ways, but planting seeds or rooting cuttings are the best methods for home growers to succeed. Learn more about how to propagate a pitcher plant and you’ll increase your collection with very little effort.
Pitcher Plant Seeds
Collect the pitcher plant seeds in late fall by pinching open the dry capsules over an envelope or piece of paper towel. Drop the seeds into a sandwich bag, along with a fungicide such as Captan, and shake the bag to coat the seeds. Pour the seeds and powder onto a new sheet of paper towel and blow off the excess powder. Spread the seeds out on a dampened paper towel, roll up the towel and store it in a zip-top bag in the refrigerator for two to three months.
Sprout the seeds by sprinkling them over a mixture of sand and peat moss. Water it and place the planter under grow lights 18 hours a day. Germination can take weeks, and the seedlings need to stay under the lights for at least four months before transplanting.
Pitcher Plant Cuttings
A faster way to propagate is by rooting pitcher plant cuttings. Cut pieces of stem that have two or three leaves on them, and clip off half of each leaf. Cut the bottom end of the stem on a diagonal and cover it with rooting hormone powder.
Fill a planter with sphagnum moss and wet it. Make a hole in the damp moss with a pencil, place the powdered stem in the hole and push the moss around the stem to secure it. Water the pot again, place it in a plastic bag and place it under grow lights. The pitcher plant cuttings should root within two months, and can be transplanted after they begin to grow new leaves.
Carnivorous Plants are generally easy to propagate. Their natural habitat, the bog, is one that can be disruptive to growing plants. Spring floods in the low wetlands often break up plants and wash them down stream. Carnivorous plants have adapted to reproducing vegetatively in order to spread and survive this stress. This features means that leaf and root cuttings can work very successfully with most carnivorous plants, especially the sundews and pitcher plants.
Methods of Propagation include:
Natural Leaf Budding
Generally speaking, the seeds of Carnivorous Plants are quite small and very slow growing. It takes a typical pitcher plant 3 to 4 years to gain a height of over 2 inches. Because of this, most Carnivorous Plants generally are not practical for classroom germination and growth. There is one nice exception: the sundews. These can germinate within a few days or weeks, grow quickly and even flower within a few months.
The best medium for seedlings is finely chopped, live green Sphagnum mixed with an equal amount of clean, washed sand. Mix and water thoroughly. The medium should be soaking wet. Sow the seeds directly on the surface. Do not overcrowd them and do not cover any Carnivorous Plant seeds with medium. Cover the growing area with plastic to keep humidity extra high. Place the seeded pots in the same growing conditions that the mature plants require. Use slightly filtered, rather than direct sunlight.
As a general rule, seeds that mature in the spring are ready for immediate sowing. Seeds that ripen in the fall must undergo a period of damp cold treatment called stratification. This can be accomplished by placing the seed-sown pot upright in a sealed plastic bag and refrigerating it for 6 to 8 weeks.
Vegetative apomixis is the growth of a plantlet along the flower spike. This can occur with the Venus Flytrap and sundews. When the plantlet develops roots it can be removed carefully and placed in a Carnivorous Plant soil mixture.
Natural Leaf Budding
Some Carnivorous Plants will develop small plants along the leaf margin. This is fairly common with the butterworts and sundews. When the buds are large enough and have developed roots of their own, they can be separated and planted in a Carnivorous Plant soil mixture.
Some Carnivorous Plants, such as the Cobra Lily, will develop plantlets along stolons or runners. These can be cut loose and replanted after they develop their own roots.
Many of the pitcher plants and some other Carnivorous Plants will naturally develop small plants along the rhizome branch. These can successfully be separated by cutting them after they develop their own roots. Plant them in a Carnivorous Plant soil mixture.
Pitcher plants can easily be propagated using rhizome cuttings. Use a large mature rhizome. Completely uncover the upper half of a horizontal rhizome of a healthy mature plant. Leave the lower rooted section intact. With a sharp, fresh, single-edged razor blade, carefully slice perpendicularly into the rhizome about halfway. Repeat this at several points about 1 inch apart. Leave the top of the rhizome uncovered, and in a few weeks new growth buds will appear at the cuts. When they develop their own roots they may be separated and planted in a Carnivorous Plant soil mixture.
Leaf cuttings work very well with sundews, moderately well with butterworts and fairly well with Venus Flytraps. This is best done in the early growing season of Spring. Cut off a fresh, healthy, mature leaf at the base of the petiole with a clean, fresh, single-edged razor blade. Place the entire leaf right-side-up on a bed of moist, finely chopped green Sphagnum. The lower side of the leaf must lie flat on the Sphagnum. You can do this by placing a single layer of cheesecloth over the leaf or by pinning it down with toothpicks. Place your pot of leaf cuttings in the shade into a plastic bag or other high humidity area. Choose a warm, but not hot place. Plantlets will occur in several weeks. Let them develop their own root systems before separating them and planting them in a Carnivorous Plant soil mixture. Slowly acclimate the new plants to their normal growing conditions. Leaf cuttings also can be placed in water to develop plantlets. This is especially useful with the sundews.
Rhizomes of many Carnivorous Plants can simply be cut into 1 inch sections and planted separately. If roots are included in the sections, take care not to damage them. This works very well with pitcher plants.
Many sundews can be propagated asexually by decapitation. Simply cut off the plant at, or just below, the soil level. Place the cut off top firmly into Carnivorous Plant soil. The top will regenerate roots and the root section of the original plant will regenerate another plant.
Carnivorous Plants can be rapidly propagated using tissue culture. The resulting plants are identical to the parent plant. This is a rather involved process and too lengthy for discussion here. Find appropriate directions and materials, and you should have good success.
Sarracenia (Pitcher Plant or Trumpet Pitcher)
Pitcher Plant Care Guide
This is a sun-loving plant and it just can’t get enough of it. During the growing season (April to October), your Pitcher Plant must get full sun, or at the bare minimum very bright light, for the pitchers to form and properly develop. South facing windows with full exposure would be this plants first and prime choice.
East and West may be suitable as a last resort, but it will need direct sun for at least a few hours a day. You may just scrape by with a bright location on a windowsill, but in almost all cases you’ll need somewhere with direct sunlight exposure for a thriving plant.
If you only have space in a North facing room then a long term relationship with this plant isn’t going to work out and you should look for something else to go in that room.
Pay attention because you need to get this right. There are two simple rules to remember –
- Keep it permanently wet – This plant needs to be wet or at the very least moist almost all year round. Do not let it dry out at all. The only exception is during the resting period in the cold months of the year at which point you need to reduce watering to prevent the rhizome rotting.
You can water very heavily, so the bottom third, or even half of the pot stands in the excess water. The native home for these plants are bogs or marshes which are constantly damp and wet. Sarracenia tend to have a thirst and this combined with the hopefully sunny spot (see above) you’re trying to grow it in will mean regular watering is a must.
- Use the right type of water – carnivorous plants need acidic water and using neutral or alkaline water for long periods will kill your plant. Once or twice in an emergency will be okay because it’s better to use the incorrect water than no water at all.
The most commonly accessible source of acidic water is rainwater. You may be able to use tap water but only if you live in a very soft water area, hard water must be avoided as it contains too many minerals. Bottled water might be okay, but if it’s been collected from springs which run through limestone the water will be slightly alkaline and so this is a no-no. Mineral water shouldn’t be used or water from fish tanks or ponds due to the high concentration of nitrates.
If you water correctly there should, in theory, be a constant source of moisture around the plant which gives a natural buff to the surrounding humidity levels. This means there is nothing additional you need do here unless you have a very dry home or place your plant in excessively dry air such as above a radiator. In this instance artificially raising the humidity level will be needed to prevent the tips of the pitchers from becoming crispy.
Pay attention, because you need to get the care requirements right
No fertiliser of any kind should be provided to your Pitcher Plants. They’re experts at dealing with nutrient-poor situations and this is why they’ve evolved to capture insects.
All the nutrients they’ll need will come from their own ability to trap pray within the pitchers and you don’t need to give them anything extra. If you never get any insets in your home (lucky you!), then consider putting your plant outside for a few weeks or so during the Summer and they’ll catch ample food during this time.
They like it warm to hot when in active growth so a typical home is perfect, and in Winter they like it cold. Really cold. Unlike almost every other houseplants they’ll happily take mild frosts when dormant.
You seldom need to repot a Sarracenia into a bigger pot unless the container you’re starting with is very small. As a base guide, consider potting on once every 2 to 3 years and this is primarily to refresh the growing medium to ensure it holds water correctly as well as removing any build up of minerals that have occurred over time.
By this point in our article, you should know already that these plants are used to a lack of nutrients, and this extends to the type of growing medium they live in. You must not use any normal houseplant compost or, as someone once asked, “dirt from the yard”.
There are lots of different mixes you can use or create yourself, but if you’re very new to these plants and don’t want to spend a long time researching growing mediums, just pick up or order some compost that’s labeled for carnivorous plants.
You can propagate Pitcher Plants from seed, but this requires two different plants to start with and then a large amount of time (3 to 5 years) to grow the plant from seed to a large enough size to produce pitchers. Instead it’s normally more efficient to use the rhizome, which is the most important part of a Pitcher plant and holds the key to successful easy propagation in most cases.
All you need to do is split a mature rhizome in half (or even smaller if you want more than two plants). It’s best to wait until early Spring when new growth is starting so it’s easier to handle and gives you a good view of where all the bits and pieces are.
Try to make sure each split of the rhizome has a few new leaves forming and some roots to give the plant the best chance of establishing. Pot up using carnivorous plant compost and treat like you would an adult plant.
Speed of Growth
With warm temperatures, excellent light levels and ample water these plants grow really fast. Several new leaves / pitchers forming each week is not unheard of.
Height / Spread
There are many varieties and hybrids which all have different growing traits. In general, your plant will be classed as either a tall or short growing variety. Most shop or store brought Pitcher Plants will be the short fairly compact growing variety and they’ll unlikely to reach more than 25cm / 10 inches.
The tall varieties grow considerably higher, up to 100cm / 3.5 ft although they normally need full outdoor exposure and for that reason tend not to make good houseplants.
Given a Winter Rest (see below) come Spring the plant will come back to life and shortly after “waking up”, it will often produce some interesting complex looking flowers that rise high above the plant and last for a few weeks. These die down and are gradually replaced by the pitchers. On our own plants’ flowers have also appeared in mid to late Summer if they’ve been treated well. They’re sometimes scented although at times the smell can be unpleasant. If you find it too overpowering then you can simply cut the flower stem off.
Is the Pitcher Plant Poisonous?
Pitcher Plants are non-toxic to cats, dogs and people.
Winter Resting Cycle
Many houseplants benefit from a Winter rest but for Pitcher Plants, it’s essential for them to stay healthy and long-lived. If you don’t follow the resting process, over time your plant will become weaker and will eventually die. The good news is that the Winter rest is very easy to do:
- Towards the middle and end of autumn (October / November in the northern hemisphere) the light and temperature levels will fall, which should then trigger the dormancy process. You’ll notice during this period that some of the growth will be dying off, turning black or just looking very tatty and this will continue for a month or so. Remove and discard the dead or tatty growth. – Pitcher Plant not showing dormancy signs?
- During this time, cut back on the watering and aim to keep the soil just damp rather than wet as you should have been doing during the Spring, Summer and early autumn.
- When growth has stopped and the existing leaves are looking tatty or have died completely (November / December) you should move your plant to a cool location for the Winter. An unheated greenhouse, porch or conservatory are all good places.
Some people even put their plants outside in a sheltered place like a shed or cold frame, although you should still take care to protect the rhizome from extreme weather conditions and excessive rainfall. Remember to only keep the soil just damp during this period and ensure there is ventilation to reduce the chances of rot or fungus attacks.
- When the heat and light levels increase again, so very late Winter / Early Spring (February / March / April) new growth will start to appear. Cut off all the tatty growth from the previous year and slowly bring it back to where it was growing prior to the rest. New leaf shoots or pitchers should start to appear fairly quickly and within a few months, your plant will be its usual self complete with many new pitchers to admire as it uses them to lure prey into once more.
The photo here shows our Pitcher Plant in Spring (end of March) after it’s completed it’s Winter rest period in an outdoor garden shed. We removed all the tatty and dead leaves and pitchers at the end of February leaving just a few inches at the base. Already you can see several new shoots growing.
How to Care for a Pitcher Plant Summary
High Light Levels Direct sunlight for at least a few hours a day is needed.
Heavy Watering Try to ensure the plant is sitting in water constantly.
Warm Temperatures Normal to warm indoor room temperatures are required when it’s growing.
Feeding No fertiliser should be provided at any time – it creates its own by catching and digesting “prey”!.
- Do not grow the plant in a North facing aspect unless you’re using a grow light
- Do not let the plant dry out at all during the growing seasons
- Do not hand feed your plant with insects
Pitcher Plant Problems
Crispy Leaves / Pitchers
This is caused by one of two things – firstly Sarracenia loves the sun, but if it’s not used to intense sunlight then the leaves / pitchers may burn and crisp as you can see in the picture below.
The second and more likely cause is that you’ve allowed the soil to dry out too much during the growing season. No Sarracenia species is forgiving of its watering requirements. You must supply a constant source of water around the roots during the growing months.
In either case hopefully, you’ve spotted the damage and corrected the problem before it became too bad. If it’s very disfiguring you can cut the damaged pitchers away and new growth will eventually fill the space.
Only producing leaves not pitchers
If the light levels are poor then this could be the result – Move to a sunnier spot. If you’re noticing this towards the end of Summer then it’s probably normal. The plant knows the Winter dormancy is coming so it conserves its energy by creating more simple leaves rather than the more complex pitchers. Give it the Winter rest and the pitchers will be back next Spring.
Pitcher Markings are fading
You must provide high levels of sunlight to keep the markings. If the light level is too low, over time existing pitchers will develop a washed out appearance and new pitchers will either be completely green or only mildly marked.
Should I feed my Pitcher Plant with dead insects?
No. The plant is adapted to capturing live prey itself. And they can catch a lot over a growing season. If you feed the plant with dead insects then it could cause issues in the long term, for example, the insects might be dead because they were poisoned which you’re now spreading into the plant.
If you really do have an insect free home and no access to put your plant outdoors occasionally then a weak houseplant feed once or twice a year might be worth considering.
Pitcher Plant not entering dormancy
It’s not known for certain exactly what triggers Pitcher Plant dormancy, the general view is that it’s the combination of lower light levels with falling temperatures. So in most cases, if your plant fails to stop growing as you approach Winter then it’s likely because it’s too warm in your home still.
The dormancy is essential for the continuous long term health of your plant, so if it’s not happening naturally move it to a cooler spot to force the process to start.
Pitcher plants are quite hardy when it comes to pests and diseases, but they can be weakened and damaged overtime by pests which attack in mass. For that reason, Aphids can be a problem and if you notice them you should take action.
About the Author
Over the last 20 years Tom has successfully owned hundreds of houseplants and is always happy to share knowledge and lend his horticulture skills to those in need. He is the main content writer for the Ourhouseplants Team.
Also on Ourhouseplants.com
Credit Sarracenia pitcher close up shot – Gallery – Geoff Gallice
Credit Pitcher Plant Sarracenia leucophylla – Article / Gallery – Xscd
Credit for the Pitcher Plant rhizome and the annotated diagrame of a pitcher – Article / Gallery – Noah Elhardt
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How Do Carnivorous Plants Reproduce?
The Fascinating Difference
Carnivorous plants are not half-animal, half-plants. They are unusual only in that they consume insects; in all other respects of their life cycle, including reproduction, carnivorous plants are the same as other plants.
Carnivorous plants consume insects for nutrients, not to produce energy. Their leaves produce energy through photosynthesis–chlorophyll in the leaves combines hydrogen from water with carbon from carbon dioxide to produce sugars that the plant needs to grow. Botanists believe that consuming insects is an evolutionary adaptation to soils that lack nitrogen; it is not relevant to the way they reproduce.
Life Cycle and Seeds
The life cycle of a carnivorous plant, as with most plants, begins with a seed. The flowers of carnivorous plants produce seeds. The seeds germinate. Seedlings grow. The plants mature, which takes less than a year for some varieties but can take longer. Depending on the amount of sunlight and competition with other plants, a Venus Flytrap can take two to four years to flower. The cycle of seed germination, plant growth, flowering and producing seeds is repeated.
In addition to reproducing by seeds, some carnivorous flowers grow small plants from the roots at their base. These small plants grow to maturity and spread in the same manner. These plants still produce flowers and seeds.
- Adamec L. Mineral nutrition of carnivorous plants – a review. Botanical Review. 1997;63:273–299.
- Adamec L. Oxygen concentrations inside the traps of the carnivorous plants Utricularia and Genlisea (Lentibulariaceae) Annals of Botany. 2007;100:849–856.
- Addicott JF. Predation and prey community structure: an experimental study of the effect of mosquito larvae on the protozoan communities of pitcher plants. Ecology. 1974;55:475–492.
- Adlassnig W. Ökophysiologie karnivorer Kesselfallenpflanzen. 2007 PhD thesis, Universität Wien, Austria.
- Adlassnig W, Mayer E, Peroutka M, Pois W, Lichtscheidl IK. The North American carnivorous plant Sarracenia in Europe. Phyton. 2010;49:279–292.
- An CI, Fukusaki E, Kobayashi A. Plasma-membrane H+-ATPases are expressed in pitchers of the carnivorous plant Nepenthes alata Blanco. Planta. 2001;212:547–555.
- An CI, Fukusaki E, Kobayashi A. Aspartic proteinases are expressed in pitchers of the carnivorous plant Nepenthes alata Blanco. Planta. 2002;214:661–667.
- Anonymous. Frankreich: Pflanze fing sich eine Maus. Kurier. (270) 2006 Wien.
- Atwater DZ, Butler JL, Ellison AM. Spatial distribution and impacts of moth herbivory on Northern Pitcher Plants. Northeastern Naturalist. 2006;13:43–56.
- Austin RM. Darlingtonia californica, Torr. Botanical Gazette. 1878;3:70–71.
- Barrera R, Fish D, Machado-Alison CE. Ecological patterns of aquatic insect communities in two Heliamphora pitcher-plant species of the Venezuelan highlands. Ecotropicos. 1989;2:31–44.
- Barthlott W, Porembski S, Seine R, Theisen I. Karnivoren. Biologie und Kultur fleischfressender Pflanzen. Stuttgart: Eugen Ulmer; 2004.
- Batalin FA. Ueber die Function der Epidermis in den Schläuchen von Sarracenia und Darlingtonia. Acta Horti Botanici Petropolitani. 1880;7:343–360.
- Bateman LE. A bdelloid rotifer living as an inquiline in leaves of the pitcher plant. Sarracenia purpurea. Hydrobiologia. 1987;147:129–133.
- Bauer U, Bohn HF, Federle W. Harmless nectar source or deadly trap: Nepenthes pitchers are activated by rain, condensation and nectar. Proceedings of the Royal Society B: Biological Sciences. 2008;275:259–265.
- Bauer U, Willems C, Federle W. Effect of pitcher age on trapping efficiency and natural prey capture in carnivorous Nepenthes rafflesiana plants. Annals of Botany. 2009;103:1219–1226.
- Bay JC. Nutrition of insectivorous plants. Botanical Gazette. 1893;18:105–106.
- Beaver RA. The communities living in Nepenthes pitcher plants: fauna and food webs. In: Frank JH, Lounibos LP, editors. Phytotelmata: terrestrial plants as hosts for aquatic insect communities. Medford: Plexus Publishing; 1983. pp. 129–159.
- Beekmann EM. A note on the priority of Rumphius’ observation of decapode crustacea living in Nepenthes. Crustaceana. 2004;77:1019–1021.
- Benzing DH. The origin and rarity of botanical carnivory. Tree. 1987;2:364–369.
- Bhattarai GP, Horner JD. The importance of pitcher size in prey capture in the carnivorous plant, Sarracenia alata Wood (Sarraceniaceae) American Midland Naturalist. 2009;161:264–272.
- Błedzki LA, Ellison AM. Population growth and production of Habrotrocha rosa Donner (Rotifera: Bdelloidea) and its contribution to the nutrient supply of its host, the northern pitcher plant, Sarracenia purpurea L. (Sarraceniaceae) Hydrobiologia. 1998;385:193–200.
- Bradshaw WE. Interaction between the mosquito Wyeomyia smithii, the midge Metriocnemus knabi, and their carnivorous host Sarracenia purpurea. In: Frank JH, Lounibos LP, editors. Phytotelmata: terrestrial plants as hosts for aquatic insect communities. Medford: Plexus Publishing; 1983. pp. 161–189.
- Bradshaw WE, Creelman RA. Mutualism between the carnivorous purple pitcher plant and its inhabitants. American Midland Naturalist. 1984;112:294–304.
- Braem G. Fleischfressende Pflanzen. Arten und Kultur. Munich: Augustus Verlag; 2002.
- Brodie J, Lee Ci. Without title. Carnivorous Plant Newsletter. 2000;29:54.
- Buckley JL, Miller TE, Ellison AM, Gotelli NJ. Reverse latitudinal trends in species richness of pitcher-plant food webs. Ecology Letters. 2003;6:825–829.
- Butler JL, Atwater DZ, Ellison AM. Red-spotted newts: an unusual nutrient source for Northern Pitcher Plants. Northeastern Naturalist. 2005;12:1–10.
- Butler JL, Gotelli NJ, Ellison AM. Linking the brown and the green: nutrient transformation and fate in the Sarracenia microcosms. Ecology. 2008;89:898–904.
- Carrow T, Hirschel K, Winkelmann H, Radke R. Fleischfressende Pflanzen: tödliche Fallen. Scientific Film: ZDF; 1997.
- Cheek M, Jebb M. Nepenthaceae. Flora Malesiana, Series I – Seed Plants. 2001;15(1 – 164)
- Chen LMJ, Chan KL. Tropical pitcher plant ecology. Predators: seed eating caterpillar. In: Tan HTW, editor. A guide to the carnivorous plants of Singapore. Singapore: Singapore Science Centre; 1997. pp. 121–124.
- Chia TF, Aung HH, Osipov AN, Goh NK, Chia LS. Carnivorous pitcher plant uses free radicals in the digestion of prey. Redox Report. 2004;9:255–261.
- Chin L, Moran JA, Clarke C. Trap geometry in three giant montane pitcher plant species from Borneo is a function of tree shrew body size. New Phytologist. 2010;186:461–470.
- Clarke C. Nepenthes of Borneo. Kota Kinabalu: Natural History Publications; 1997.
- Clarke C. A re-examination of geographical variation in Nepenthes food webs. Ecography. 1998;21:430–436.
- Clarke C, Kitching RL. The metazoan food webs from six Bornean Nepenthes species. Ecological Entomology. 1993;18:7–16.
- Clarke CM, Kitching RL. Swimming ants and pitcher plants: a unique ant–plant interaction from Borneo. Journal of Tropical Ecology. 1995;11:589–602.
- Clarke C, Moran J, Merbach M, Frazier C, Chua L. Nepenthes of Summatra and peninsular Malaysia. Kota Kinabalu: Natural History Publications (Borneo); 2001.
- Clarke CM, Bauer U, Lee CC, Tuen AA, Rembold K, Moran JA. Tree shrew lavatories: a novel nitrogen sequestration in a tropical pitcher plant. Biology Letters. 2009;5:632–635.
- Clarke SA. Seasonal growth and mortality of the pitchers of the Albany Pitcher Plant, Cephalotus follicularis Labill. Australian Journal of Botany. 1988;36:643–653.
- Cochran-Stafira DL, von Ende CN. Integrating bacteria into food webs: studies with Sarracenia purpurea inquilines. Ecology. 1998;79:880–898.
- Cochran-Stafira DL, Yakimova E. Sarracenia purpurea pitchers: potential oviposition sites for mosquito vectors of arboviral encephalitis? 88th Annual Meeting of the Ecological Society of America. 2003 Savannah.
- Cresswell JE. Capture rates and composition of insect prey of the pitcher plant Sarracenia purpurea. American Midland Naturalist. 1991;125:1–9.
- Cresswell JE. The morphological correlates of prey capture and resource parasitism in pitchers of the carnivorous plant Sarracenia purpurea. American Midland Naturalist. 1992;129:35–41.
- Cresswell JE. Morphological correlates of necromass accumulation in the traps of an Eastern tropical pitcher plant, Nepenthes ampullaria Jack, and observations on the pitcher infauna and its reconstitution following experimental removal. Oecologia. 1998;113:383–390.
- Cresswell JE. Resource input and the community structure of larval infaunas of an eastern tropical pitcher plant Nepenthes bicalcarata. Ecological Entomology. 2000;25:362–366.
- D’Amato P. Cultivating carnivorius plants. Berkely: Ten Speed Press; 1998. The savage garden.
- Dakin WJ. The West Australian pitcher plant (Cephalotus follicularis) and its physiology. Journal of the Royal Society of Western Australia. 1917;4:37–53.
- Devečka A. Diversität der Nepenthes-Falle unter besonderer Berücksichtigung der Oberflächenstrukturen und ihrer Rolle beim Beutefang. Diploma Thesis, Technical University Zvolen: Slovakia; 2007.
- Di Giusto B, Grosbois VV, Fargeas E, Marshall DJ, Gaume L. Contribution of pitcher fragance and fluid viscosity to high prey diversity in a Nepenthes carnivorous plant from Borneo. Journal of Biosciences. 2008;33:121–136.
- Eilenberg H, Pnini-Cohen S, Schuster S, Movtchan A, Zilberstein A. Isolation and characterization of chitinase genes from pitchers of the carnivorous plant Nepenthes khasiana. Journal of Experimental Botany. 2006;57:2775–2784.
- Eilenberg H, Zilberstein A. Carnivorous pitcher plants – towards understanding the molecular basis of prey digestion. In: Teixeira da Silva JA, editor. Floriculture, ornamental and plant biotechnology. advances and topical issues. Isleworth: Global Science Books; 2008. pp. 287–294.
- Ellison AM. Turning the tables: plants bite back. Fall. 2005;2005:25–30.
- Ellison AM. Nutrient limitation and stoichiometry of carnivorous plants. Plant Biology. 2006;8:740–747.
- Ellison AM, Gotelli NJ. Evolutionary ecology of carnivorous plants. Trends in Ecology and Evolution. 2001;16:623–629.
- Ellison AM, Gotelli NJ. Effects of nutrient stress on a co-evolved food web. 14th Annual Harvard Forest Ecology Symposium. 2003 Harvard.
- Fashing NJ. Mate-guarding in the genus Creutzeria (Astigmata: Histiostomatidae), an aquatic mite genus inhabiting the fluid-filled pitchers of Nepenthes plants (Nepenthaceae) Systematic and Applied Acarology. 2008;13:163–171.
- Figueira JEC, Vasconcellosneto J, Jolivet P. A new protocarnivorous plant from Brasil, Paepalanthus bromelioides Silv. (Eriocaulaceae) Revue d’Ecologie-La Terre et la Vie. 1994;49:3–9.
- Frank JH, Fish D. Potential diversity loss in Florida bromeliad phytotelmata due to Metamasius callizona (Coleoptera: Dryophthridae), an invasive species. Florida Entomologist. 2008;91:1–8.
- Frazier CK. The enduring controversies concerning the process of protein digestion in Nepenthes (Nepenthaceae) Carnivorous Plant Newsletter. 2000;29:56–61.
- Fuller GD. Animal parasites of Nepenthes. Botanical Gazette. 1912;53:264–265.
- Gallie DR, Chang S-C. Signal transduction in the carnivorous plant Sarracenia purpurea. Plant Physiology. 1997;115:1461–1471.
- Gaume L, Forterre Y. A viscoelastic deadly fluid in carnivorous pitcher plants. PLoS ONE. 2007;2:e1185. doi:10.1371/journal.pone.0001185.
- Gebühr C, Pohlon E, Schmidt AR, Küsel K. Development of the microalgae communities in the phytotelmata of Sarracenia purpurea L. XVII International Botanical Congress. 2005 Vienna.
- Gebühr C, Pohlon E, Schmidt AR, Küsel K. Development of microalgae communities in the phytotelmata of allochthonous populations of Sarracenia purpurea (Sarraceniaceae) Plant Biology. 2006;8:849–860.
- Givnish TJ. Ecology and evolution of carnivorous plants. In: Abrahamson WG, editor. Plant–animal interactions. New York: McGraw-Hill; 1989. pp. 243–290.
- Givnish TJ, Burkhardt EL, Happel RE, Weintraub JD. Carnivory in the bromeliad Brocchinia reducta, with a cost/benefit model for the general restriction of carnivorous plants to sunny, moist, nutrient-poor habitats. The American Naturalist. 1984;124:479–497.
- Goebel K. Organographie der Pflanzen, insbesondere der Archegoniatan und Samenpflanzen. Dritter Teil. Samenpflanzen. Erste Hälfte. Jena: Gustav Fischer; 1932.
- Gonzalez JM, Jaffe K, Michelangeli F. Competition for prey between the carnivorous Bromeliaceae Brocchinia reducta and Sarraceniaceae Heliamphora nutans. Biotropica. 1991;23:602–604.
- Gotelli NJ, Ellison AM. Food-web models predict species abundances in response to habitat change. PLoS Biology. 2006;4:e324. doi:10.1371/journal.pbio.0040324.
- Gray SM, Miller TE, Mouquet N, Daufresne T. Nutrient limitation in detritus-based microcosms in Sarracenia purpurea. Hydrobiologia. 2006;573:173–181.
- H.M.R. Proteolytic enzyme of Nepenthes. American Naturalist. 1899;33:272.
- Hamilton R, Duffield RM. Novel observations of midge and mosquito larval dynamics in leaves of the northern pitcher plant, Sarracenia purpurea L. Hydrobiologia. 2002;482:191–196.
- Hartmeyer SRH. Sarracenia purpurea am ‘Naturstandort’ in der Schweiz. Das Taublatt. 1996;28:11–15.
- Harvey E, Miller TE. Variance in composition of inquiline communities in leaves of Sarracenia purpurea L. on multiple spatial scales. Oecologia. 1996;108:562–566.
- Hatano N, Hamada T. Proteome analysis of pitcher fluid of the carnivorous plant Nepenthes alata. Journal of Proteome Research. 2008;7:809–816.
- Haubrich CS, Pires APF, Esteves FA, Farjalla VF. Bottom-up regulation of bacterial growth in tropical phytotelm bromeliads. Hydrobiologia. 2009;632:347–353.
- Heard SB. Imperfect oviposition decisions by the pitcher plant mosquito (Wyeomyia smithii) Evolutionary Ecology. 1994a;8:493–502.
- Heard SB. Pitcher-plant midges and mosquitoes: a processing chain commensalism. Ecology. 1994b;75:1647–1660.
- Heard SB. Capture rates of invertebrate prey by the pitcher plant, Sarracenia purpurea L. American Midland Naturalist. 1997;139:79–89.
- Hegner RW. The protozoa of the pitcher plant, Sarracenia purpurea. Biological Bulletin. 1926;50:271–276.
- Hepburn JS. Biochemical studies of the pitcher liquor of Nepenthes. Proceedings of the American Philosophical Society. 1918;57:112–129.
- Hepburn JS, St. Jones FM, John EQ. The biochemistry of the American pitcher plants: biochemical studies of the North American Sarraceniaceae. Transactions of the Wagner Free Institute of Science of Philadelphia. 1927;11:1–95.
- Higashi S, Nakashima A, Ozaki H, Abe M, Uchiumi T. Analysis of feeding mechanism in a pitcher of Nepenthes hybrida. Journal of Plant Research. 1993;106:47–54.
- Hooker JD. The carnivorous habits of plants. Nature. 1874;10:366–372.
- Hua YJ. 5th I.C.P.S. Congress. Lyon: International Carnivorous Plant Society; 2004. Nepenthes and its food web. In: ICP Society. ed.
- Hua YJ, Kuizheng L. The special relationship between Nepenthes and tree frogs. Carnivorous Plant Newsletter. 2004;33:23–24.
- Hughes RN, Brimblecombe P. Dew and guttation – formation and environmental significance. Agricultural and Forest Meteorology. 1994;67:173–190.
- Istock CA, Tanner K, Zimmer H. Habitat selection by the pitcher-plant mosquito, Wyeomyia smithii: behavioral and genetic aspects. In: Frank JH, Lounibos LP, editors. Phytotelmata: terrestrial plants as hosts for aquatic insect communities. Medford: Plexus Publishing; 1983. pp. 191–204.
- Jabiol J, Corbara B, Dejean A, Cereghino R. Structure of aquatic insect communities in tank-bromeliads in an East-Amazonian rainforest in French Guiana. Forest Ecology and Management. 2009;257:351–360.
- Jaffe K, Michelangeli F, Gonzalez JM, Miras B, Ruiz MC. Carnivory in pitcher plants of the genus Heliamphora (Sarraceniaceae) New Phytologist. 1992;122:733–744.
- James JF. Pitcher plants. American Naturalist. 1883;17:283–293.
- Jentsch J. Enzymes from carnivorous plants (Nepenthes). Isolation of the protease nepenthacin. FEBS Letters. 1972;21:273–276.
- Joel DM, Heide-Jørgenson HS. Ultrastructure and development of the pitcher epithelium of Sarracenia. Israel Journal of Botany. 1985;34:331–349.
- Jones FM. Pitcher-plant insects – II. Entomological News. 1907;18:412–420.
- Jones FM. Pitcher-plant insects – III. Entomological News. 1908;19:150–156.
- Jones FM. Pitcher plants and their moths. Natural History. 1921;21:296–316.
- Juniper BE, Robins RJ, Joel DM. The carnivorous plants. London: Academic Press Limited; 1989.
- Jürgens A, El-Sayed AM, Suckling DM. Floral scent in a whole-plant context: do carnivorous plants use volatiles for attracting prey insects? Functional Ecology. 2009;23:875–887.
- Kajii E, Kamesaki T, Ikemoto S, Miura Y. Decomposing enzymes against human blood-group antigens in the extract of Nepenthes alata. Naturwissenschaften. 1988;75:258–259.
- Kamesaki T, Kajii E, Ikemoto S. Purifikation of the decomposing enzyme from Nepenthes alata against glycophorin B of human red blood cells by high-performance liquid chromatography. Journal of Chromatography. 1989;489:384–389.
- Karagatzides JD, Ellison AM. Construction costs, payback times, and the leaf economics of carnivorous plants. American Journal of Botany. 2009;96:1612–1619.
- Karagatzides JD, Butler JL, Ellison AM. The pitcher plant Sarracenia purpurea can directly acquire organic nitrogen and short-circuit the inorganic nitrogen cycle. PLoS One. 2009;4:e6164. doi:10.1371/journal.pone.0006164.
- Kingsolver JG. Thermal and hydric aspects of environmental heterogenity in the pitcher plant mosquito. Ecological Monographs. 1979;49:357–376.
- Kingsolver JG. The effect of environmental uncertainity on morphological design and fluid balance in Sarracenia purpurea L. Oecologia. 1981;48:364–370.
- Kitching RL. Food webs and container habitats. The natural history and ecology of phytotelmata. Cambridge: Cambridge University Press; 2000.
- Kitching RL. Food webs in phytotelmata. Annual Review of Entomology. 2001;46:729–760.
- Kneitel JM, Miller TE. Dispersal rates affect species composition in metacommunities of Sarracenia purpurea inquilines. American Naturalist. 2003;162:165–171.
- Laessle AM. A micro-limnological study of Jamaican bromeliads. Ecology. 1961;42:499–517.
- Lim KKP, Ng PKL. Nepentophilous larvae and breeding habitats of the sticky frog, Kalophrynus pleurostigma Tschudi (Amphibia: Microhylidae) Raffles Bulletin of Zoology. 1991;39:209–214.
- Lindquist J. Bacteriological and ecological observations of the Northern Pitcher Plant, Sarracenia purpurea L. Carnivorous Plant Newsletter. 1975;4:65–66.
- Lloyd FE. The carnivorous plants. New York: Ronald Press; 1942.
- Lösch R. Wasserhaushalt der Pflanzen. Wiesbaden: Quelle & Meyer; 2001.
- Lüttge U. Untersuchungen zur Physiologie der Carnivoren-Drüsen. I. Die an den Verdauungsvorgängen beteiligten Enzyme. Planta. 1964;63:103–117.
- Lüttge U. Untersuchungen zur Physiologie der Carnivoren Drüsen: IV. Die Kinetik der Chloridsekretion durch das Drüsengewebe von Nepenthes. Planta. 1966a;68:44–56.
- Lüttge U. Untersuchungen zur Physiologie der Carnivoren Drüsen: V. Mikroautoradio-graphische Untersuchungen der Chloridsekretion duch das Drüsengewebe von Nepenthes. Planta. 1966b;68:269–285.
- MacMillan C. Notes on fungi affecting leaves of Sarracenia purpurea in Minnesota. Bulletin of the Torrey Botanical Club. 1891;18:214–215.
- Mattews REF. A ribonuclease from Nepenthes spp. Biochimica et Biophysica Acta. 1960;38:552–553.
- Mayer E. Karnivore Kesselfallenpflanzen – Untersuchungen zur Verdauung, Nährstoffaufnahme und Mikroflora. Austria: University of Vienna; 2005. Diploma Thesis.
- McPherson S. Fleischfressende Pflanzen im Hochland von Guayana. Das Taublatt. 2007a;57:38–49.
- McPherson S. Pitcher plants of the Americas. Blacksburg: McDonald and Woodward Publishing Company; 2007b.
- Meir P, Juniper BE, Evans DE. Regulation of free calcium concentrations in the pitchers of the carnivorous plant Sarracenia purpurea: a model for calcium in the higher plant apoplast? Annals of Botany. 1991;68:557–561.
- Merbach MA, Merbach DJ, Maschwitz U, Booth WE, Fiala B, Zizka G. Mass march of termites into the deadly trap. Nature. 2002;415:36–37.
- Merbach MA, Zizka G, Fiala B, Merbach D, Booth WE, Maschwitz U. Why a carnivorous plants cooperates with an ant – selective defense against pitcher-destroying weevils in the myrmecophytic pitcher plant Nepenthes bicalcarata Hook. F. Ecotropica. 2007;13:45–56.
- Miller TE, Ellison AM, Gotelli N, Buckley H. w. y. Biocomplexity project: a synthetic approach to phytotelmata communities. http://bio.fsu.edu/~miller/Biocomplexity/introduction.html . Accessed 23/09/2010.
- Miller TE, Cassill D, Johnson C, et al. Intraspecific and interspecific competion of Wyeomyia smithii (Coq.) (Culicidae) in pitcher plant communities. American Midland Naturalist. 1994;131:136–145.
- Miller TE, Kneitel JM, Burns JH. Effect of community structure on invasion success and rate. Ecology. 2002;83:898–905.
- Ming LT. Chordate. In: Tan HTW, editor. A guide to the carnivorous plants of Singapore. Singapore: Singapore Science Centre; 1997. pp. 155–157.
- Mogi M, Yong HS. Aquatic arthropod communities in Nepenthes pitchers: the role of niche differentiation, aggregation, predation and competition in community organization. Oecologia. 1992;90:172–184.
- Molisch H. Über den Wasserkelch der Blütenknospen von Aconitum variegatum. Berichte der Deutschen Botanischen Gesellschaft. 1921;39:34–346.
- Moran JA. Pitcher dimorphism, prey composition and the mechanisms of prey attraction in the pitcher plant Nepenthes rafflesiana in Borneo. Journal of Ecology. 1996;84:515–525.
- Moran JA, Moran AJ. Foliar reflectance and vector analysis reveal nutrient stress in prey-deprived pitcher plants (Nepenthes rafflesiana) International Journal of Plant Sciences. 1998;159:996–1001.
- Moran JA, Merbach MA, Livingston NJ, Clarke CM, Booth WE. Termite prey spezialisation in the pitcher plant Nepenthes albomarginata – evidence from stable isotope analyis. Annals of Botany. 2001;88:307–311.
- Moran JA, Clarke CM, Hawkins BJ. From carnivore to detritivore? Isotopic evidence for leaf litter utilization by the tropical pitcher plant Nepenthes ampullaria. International Journal of Plant Sciences. 2003;164:635–639.
- Moran JA, Hawkins BJ, Gowen BE, Robbins SL. Ion fluxes across the pitcher walls of three Bornean Nepenthes pitcher plant species: flux rates and gland distribution patterns reflect nitrogen sequestration strategies. Journal of Experimental Botany. 2010;61:1365–1374.
- Morrissey SM. Chloride ions in the secretion of the pitcher plant. Nature. 1955;176:1220–1221.
- Morrissey SM. The secretion of acid by Nepenthes. Journal of Physiology. 1960;150:16–17.
- Müllner BC. Nachweis von mikrobiellen Symbionten karnivorer Kannenpflanzen anhand von 16S rRNA und Kulturmethoden. Austria: University of Vienna; 2009. MSc Diploma thesis.
- Müllner BC, Adlassnig W, Mayer E, Lichtscheidl IK. Microorgansims as symbionts of carnivorous pitcher plants: bacteria, fungi and protists in traps of Nepenthes ventrata and Sarracenia purpurea. Physologia Plantarum. 2008;133:P05–P042.
- Naeem S. Resource heterogenity fosters coexistence of a mite and a midge in pitcher plants. Ecological Monographs. 1988;58:215–227.
- Napp-Zinn K. Experimentelle und ökologische Anatomie des Angiospermenblattes. C. Karnivore Angiospermen. In: Braun HJ, Carlquist S, Ozenda P, Roth I, editors. Handbuch der Pflanzenanatomie. Berlin: Gebrüder Borntraeger; 1984. pp. 394–422.
- Newell SJ, Nastase AJ. Efficiency of insect capture by Sarracenia purpurea (Sarraceniaceae), the northern pitcher plant. American Journal of Botany. 1998;85:88–91.
- Ng PKL, Lim RP. The taxonomy and biology of the nepenthifilous freshwater sesarmine crap, Geosesarma malayanum Ng and Lim, 1986 (Crustaceae, Decapoda, Brachyura, Grapsidae) from peninsula Malaysia. Malayan Nature Journal. 1987;41:393–402.
- Okahara K. Physiological studies on Drosera IV: on the function of micro-organisms in the digestion of insect bodies by insectivorouse plants. Scientific Reports of Tohoku Imperial University. 1933:151–168.
- Peroutka M, Adlassnig W, Lendl T, Pranic K, Lichtscheidl IK. Functional biology of carnivorous plants. In: Teixeira da Silva JA, editor. Floriculture, ornamental and plant biotechnology. Advances and topical issues. Isleworth: Global Science Books; 2008. pp. 266–287.
- Petersen RL, Faust A, Nagawa J, Thomas C, Vilmenay A. Foreign mosquito survivorship in the pitcher plant Sarracenia purpurea – the role of the pitcher-plant midge Metriocnemus knabi. Hydrobiologia. 2000;439:13–19.
- Petersen RL, Hanley L, Walsh E, Hunt H, Duffield RM. Occurence of the rotifer, Habrotrocha cf. rosa Donner, in the purple pitcher plant, Sarracenia purpurea L., (Sarraceniaceae) along the eastern seabord of North America. Hydrobiologia. 1997;354:63–66.
- Plummer GL, Jackson TH. Bacterial activities within the sarcophagus of the insectivorous plant, Sarracenia flava. American Midland Naturalist. 1963;69:462–469.
- Plummer GL, Kethley JB. Foliar absorption of amino-acids, peptides and other nutrients by the pitcher-plant Sarracenia flava. Botanical Gazette. 1964;125:245–260.
- Pranjic K, Adlassnig W, Stoecker K, Daims H, Peroutka M, Lichtscheidl IK. A microscopical search for putative mutualistic micro-organisms in carnivorous plants. Botanical Microscopy Meeting. 2007 Salzburg.
- Prankevicius AB, Cameron DM. Bacterial dinitrogen fixation in the leaf of the northern pitcher plant (Sarracenia purpurea) Canadian Journal of Botany. 1991;69:2296–2298.
- Ratsirarson J, Silander JA. Structure and dynamics in Nepenthes madagascariensis pitcher plant micro-communites. Biotropica. 1996;28:218–227.
- Reid JW. A human challenge: discovering and understanding continetal copepod habitats. Hydrobiologia. 2001;453/454:201–226.
- Rice B. Carnivorous plants with hybrid trapping strategies. Carnivorous Plant Newsletter. 2007;36:23–27.
- Riley CV. Pitcher-plant insects. Nature. 1874;10:463–465.
- Rischer H, Hamm A, Bringmann G. Nepenthes insignis uses a C2-portion of the carbon skeleton of l-alanine acquired via its carnivorous organs, to build up the allelochemical plumbagin. Phytochemistry. 2002;59:603–609.
- Rumphius GE. Het Amboinsche kruitboek. Amsterdam: Joannes Burmannus; 1750.
- Schoenwetter T, Lyon LM, Hardesty LH, Seddon W. The use of Nepenthes madagascariensis in traditional medicine and healing among the people of Fort Dauphin, Madagascar. 6th Conference of the International Carnivorous Plant Society. 2006 Frostburg.
- Schulze W, Schulze ED, Pate JS, Gillison AN. The nitrogen supply from soils and insects during growth of the pitcher plants Nepenthes mirabilis, Cephalotus follicularis and Darlingtonia californica. Oecologia. 1997;112:464–471.
- Schulze W, Frommer WB, Ward JM. Transporters for ammonium, amino acids and peptides are expressed in pitchers of the carnivorous plant Nepenthes. The Plant Journal. 1999;17:637–646.
- Schulze W, Schulze ED, Schulze I, Oren R. Quantification of insect nitrogen utilization by the venus fly trap Dionaea muscipula catching prey with highly variable isotope signatures. Journal of Experimental Botany. 2001;52:1041–1049.
- Schwartz SS, Jenkins DG. Temporary aquatic habitats: constraints and opportunities. Aquatic Ecology. 2000;34:3–8.
- Smith JG. Recent studies of carnivorous plants. American Naturalist. 1893;27:413–420.
- Sota T, Mogi M, Kato K. Local and regional-scale food web structure in Nepenthes alata pitchers. Biotropica. 1998;30:82–91.
- Steckelberg R, Lüttge U, Weigl J. Reinigung der Proteinase aus Nepenthes-Kannensaft. Planta. 1967;76:238–241.
- Stehli G. Pflanzen auf Insektenfang. Schilderungen aus dem Leben von fleischfressenden und insektenfangenden Pflanzen. Stuttgart: Kosmos, Gesellschaft der Naturfreunde; 1934.
- Streble H, Krauter D. Das Leben im Wassertropfen. Mikroflora und Mikrofauna des Süßwassers. Ein Bestimmungsbuch. Stuttgart: Franckh-Kosmos-Verlags-GmbH & Co; 2002.
- Studnicka M. Observations on life strategies of Genlisea, Heliamphora, and Utricularia in natural habitats. Carnivorous Plant Newsletter. 2003;32:57–61.
- Swales DE. Sarracenia purpurea as host and carnivore at Lac Carre, Terrebonne County, Quebec. Canadian Naturalist. 1972;99:41–47.
- Takahashi K. Variations in the content and isozymic composition of nepenthesin in the pitcher fluids among Nepenthes species. Carnivorous Plant Newsletter. 2007;36:73–76.
- Takahashi K, Matsumoto K, Nishii W, Muramatsu M, Kubota K. Comparative studies on the acid proteinase activities in the digestive fluids of Nepenthes, Cephalotus, Dionaea, and Drosera. Carnivorous Plant Newsletter. 2009;38:75–82.
- Tan HTW. Prey. In: Tan HTW, editor. A guide to the carnivorous plants of Singapore. Singapore: Singapore Science Centre; 1997. pp. 125–131.
- Tan HTW, Ng PKL. Digestion and early succession in the pitcher-fluid. In: Tan HTW, editor. A guide to the carnivorous plants of Singapore. Singapore: Singapore Science Centre; 1997. pp. 132–138.
- Taylor P. The genus Utricularia – a taxonomic monograph. 1994. London: Royal Botanic Gardens, Kew.
- Tökés ZA, Woon WC, Chambers SM. Digestive enzymes secreted by the carnivorous plant Nepenthes macfarlanei L. Planta. 1974;119:39–46.
- Treat M. Plants that eat animals. American Naturalist. 1875;9:658–662.
- Trzcinski MK, Waldis SJ, Tayler PD. Stability of pitcher-plant microfaunal populations depends on food web structure. Oikos. 2005;110:146–154.
- van Oye P. Zur Biologie der Kanne von Nepenthes melamphora Reinw. Biologisches Zentralblatt. 1921;41:529–534.
- Vines SH. The physiology of pitcher plants. Journal of the Royal Horticultural Society. 1897;21:92–112.
- Wagner M, Aßmus B, Hartmann A, Hutzler P, Amann R. In situ analysis of microbial consortia in activated sludge using fluorescently labeled, rRNA-targeted oligonucleotide probes and confocal scanning laser microscopy. Journal of Microscopy. 1994;176:181–187.
- Williams DD. Environmental constraints in temporary fresh waters and their consequences for the insect fauna. Journal of the North American Benthological Society. 1996;15:634–650.
- Williams DD. The biology of temporary waters. Oxford: Oxford University Press; 2006.
- Zavortink TJ. Zinzala, a new subgenus of Wyeomyia with two new species from pitcher-plants in Venezuela (Diptera, Culicidae, Sabethini) Wasmann Journal of Biology. 1985;43:46–59.
By S. Roger Horman
Pitcher plants thrive in sunlit bogs, where the soil is constantly moist, acidic and contains few nutrients. Propagation from seed is best performed with these factors in mind. The process described below includes:
- When to plant
- Separation of seeds from their pods,
- Measuring the right number of seeds to plant by counting, weighing or volume,
- Making the planting mix,
- Filling the pots,
- Planting the seeds,
- Making and installing protective tents for the pots,
- Providing constant moisture, and
- Repotting the plants when this is needed.
Pitcher plant seeds are formed in the 5-carpellate ovaries of the flowers. The structure of the flower, as shown below in figure 2(a), maintains this five-fold symmetry, and shields the ovary during much of its development behind a highly modified umbrella-like style. When the ovary has matured, it will become dry and take on a tan to reddish brown color, figure 2(b). The number of seeds per ovary is highly variable, ranging from a few to hundreds. The size of the seeds is also highly variable between species and from different plants within species due to environmental factors and maturity of the parent plant.
When the capsule has dried completely, the ovaries are ready for harvesting. To prevent loss of seeds, they can be cut while still green in late August. Frequently, the ovaries will split open like the lower one in figure 2(b), but some will remain tightly sealed like the upper capsule in that figure. The seeds are easy to remove from the ovary with the fingers aided by a dental pick. Because it is easy to confuse debris from the ovary with the seeds, it is best to try to remove the seeds without crushing and scattering the ovaries. A dental pick or a very small brush can be used to remove debris from the seeds. This can be tedious with a large volume of seeds, therefore it is recommended that only a single ovary be processed at a time and clean seeds be removed from the work area and stored in a vial or bottle with a top. The seeds should be stored in paper envelopes in a cool place such as a refrigerator.
The best time to plant is in mid winter. Planting of the seeds is best done in pots with a nominal volume of 1 gallon. Although there is no set rule about the number of seeds to be planted in each pot, 100 seeds seems to work out well. This is actually a small volume of seeds, as can be seen in figure 1. If you do not intend to measure germination and survival rates, you can approximate 100 seeds by measuring the weight or volume of a small volume of seeds, count the seeds measured, using a dental pick or a small brush, and then use this information to approximate 100 seeds. For example, figure 3 shows a scoop fabricated from a previously fired .22 caliber long rifle casing and wire. It tended to contain approximately 150 Sarracenia flava seeds on several trials. Remember, the size of seeds is highly variable, so do not assume that this scoop will even approximate the count that you will get with your seeds. If you want to measure germination rates, there is no way around counting the seeds.
The planting mixture for virtually all North American pitcher plant seeds is an even mixture (by volume) of masonry sand and peat moss. The best way to mix large volumes of peat moss and sand is in a wheel barrow or on the ground. The two materials should be mixed well, as if you were mixing concrete. Add water as you mix and thoroughly hydrate the peat to the point that you can squeeze the soil and see water, but not to the point that you can make the soil a soup. If the pots are used, it is recommended that they be sterilized by washing with bleach and detergent, followed by thorough rinsing and air drying.
When completed, the mixture should appear uniform as in the case of figure 4.
Next, pine needles should be pressed into the bottom of the pot until the compressed needles completely cover the drainage holes plus a quarter of an inch (about 5-10 mm). The purpose of the pine needles is to prevent loss of the planting mix through the drain holes in the pots. This loss in turn can lead to slumping of the mix in the pots and damage or loss of plants. We have also used a double thickness of institutional coffee filters, which works well at first, but which frequently rots and fails. The pine needles last well and do a good job of retaining the planting mix. Add the planting mixture to each pot being careful to press the mixture in firmly to avoid voids in the mix. The soil level should be approximately one quarter to one half inch from the top of the pot. Insert an 18 inch (approximately 45 cm) long stake firmly into the pot, taking care that the stake is vertical (see figure 5.) Afterwards, take care to press the mixture surface such that it is as flat and level as possible. Next gently tap the seeds from the seed container as evenly as possible over the entire surface of the mixture in the pot. Do not bury them or water them on top. The seeds are very hydrophobic and direct surface watering will result in the seeds floating away. Handling of the seeds with fingers or other tools may also result in the unwanted transfer of seeds to other experimental pots. Do not bury them. A tent of unwoven fabric or the tubular cloth covering made for drain tile (see http://www.carriff.com) will protect the seeds and seedlings from most of the negative effects of rain and adverse weather, as well as provide some protection from large insects.We make ours approximately 13 inches (33 cm) high, and attach the top to the stake with a “twist tie” and, if tents of unwoven fabric are used, the bottom to the pot with rubber bands. The rubber bands will degrade in sunlight, but normally will remain effective until the seedlings are ready to live without the protection of the tent, about 6-9 months (figures 6 and 7.) The tubular cloth tents have an elastic nature, which allows them to be used without the rubber bands.
The pots should be placed snugly together in a flooded bed with water maintained at a constant level of about 1/3rd to 1/2 pot height. We have found that an automatic watering system, coupled with a drain the height of which determines the water depth, prevents accidents such as letting the pots dry out. Since drying is frequently fatal to the seedlings, care must be taken to check the water depth on a regular basis, even if an automatic watering system is used. Reference to the Potomac Elementary School (Dahlgren, VA) site will provide photographs of such a flooded bed and watering system.
One of the most efficient ways to break dormancy in the seeds and prepare them for germination is to sow them on the surface of the prepared pots in mid-winter. Once the seeds are sown, the tents are placed over the pot, and the whole assembly is placed outside in the tank of water maintained at 1/3rd to 1/2 pot height. The freezing and thawing which occurs over the winter months breaks dormancy in the seed and the tent prevents seed loss. Furthermore, since the seeds have already been sown in the pot they can then germinate and grow in the spring under the protected conditions provided by the tent. Pitcher plant seeds typically germinate outside during May in the mid-Atlantic states. The tents will prevent damage to the tender seedlings from severe storm events during the summer months. Tents may then be removed in mid to late summer.
If one desires to germinate pitcher plant seeds and raise seedlings indoors under lights during the winter, the following changes may be made. After one month of freezing and thawing bring the pots inside. Place the pots in water maintained at 1/3 the height of the pot. Cool white flourescent lights, with an 18 hour photoperiod, may then be placed 10cm from the top of the pot. Germination will begin within two to three weeks. Instructions for building light stands are provided on the Potomac Elementary School web site.
Depending on the quality of the seeds and the water used, germination rates from 1% to 84% can be expected. Because most of the water consumed by the evaporation from the pot comes from the base and not the top, hard water can cause a build-up of toxic minerals called caliche. Caliche formation can be avoided by use of soft water, distilled water or rainwater. However, unless you are growing a small number of pots, the amount of water consumed during the summer months in a climate like that of Virginia will require more water than can normally be collected in a rain barrel.
The seeds will germinate in 3-8 weeks after the last thaw, but will have very short roots. This is the main reason why the use of tents is critical. The young sprouts are easily dislodged and moved, even to the point of being knocked out of the pot, by rain drops which hit them directly. The sprouts will look like very tiny pitcher plants from the beginning. If weed seeds were in your sand or peat moss you will see a very prompt and healthy germination of them as well. Take care when pulling weeds, but normally there will be no question of the difference between them and the little pitcher plants. If weeds are allowed to get too tall, their root structure is usually extensive compared to that of the pitcher plants. This will require a careful touch to tease the weeds out of the mix without dislodging the pitcher plants. Figure 8 shows what a pot of pitchers looks like about one year after germination, when grown outside in soft well water.
It is possible to force the growth of pitcher plants indoors during winter through use of fluorescent lighting in a heated room. Reference to the Potomac Elementary School Website, devoted to work performed with the assistance of grants from Toyota, the National Science Teachers Association and Virginia Power, will provide detailed information concerning how to make light tables and show the dramatic growth possible through this forced growth. It is important to allow the seedlings to go dormant for a few weeks prior to bringing them inside.
Regardless of the method by which the seedlings are raised, outdoors or forced inside under lights, the time to transplant small seedlings from crowded pots is in early Spring. We do not recommend transplanting seedlings in the Fall. Fall transplant of seedlings results in a greater likelihood of mortality due to freezing effects on the poorly rooted plants.Disturb the roots as little as possible. If it is possible to remove the plant and a core of soil containing all its roots, this is recommended. If you are transplanting a large number, either transplant them one at a time or place the seedlings in water to avoid desiccation until they are ready to plant.
It generally takes 5-7 years from planting of a seed until the plant reaches sexual maturity and blooms. This can be somewhat accelerated by ideal growing conditions and/or a winter of forced growth under lights. Continued forced growth beyond a year is frequently detrimental, so it should be viewed as a means to get the plants to a size and state where they will be more likely to survive on their own.
The plants in figures 8 (a) and 8 (b) are hybrids, which can be beautiful and surprising in your gardens. You should not plant hybrids into the wild, nor plant known species into the wild except into areas of their current or historic range. This is important to prevent any further deterioration of pitcher plant stands in the wild and to avoid competition with attempts to restore threatened and endangered plants to their historic ranges.