Learn how to Grow and Use Carnivorous Plants
A correspondence course for the enthusiast or commercial grower.
Carnivor Plants are unique.
They don’t appeal to everyone; but they often capture the imagination of people who are not necessarily interested in other types of plants.
Anyone who chooses to undertake this course is obviously interested in carnivorous plants; probably either as an amateur collector, a commercial grower or a naturalist.
Carnivorous plants are plants that derive some or all of their nutrients by capturing and digesting small animals, such as insects. Other terms used for carnivorous plants are a “carnivory” or a “carnivore”. The mechanisms used to capture and digest animals are generally subtle; but not always. Characteristics that are unique to carnivorous plants include:
- Attraction Mechanisms eg. Lures, odors, directional guides
- Trapping Mechanisms eg. Sticky secretions that hold animals like fly paper, trap door like openings to digestive chambers.
- Digestive Mechanisms eg. Secreted enzymes and absorption of digested material.
Lesson Structure
There are 9 lessons in this course:
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Introduction -characteristics and classification, resources, etc.
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Culture -soils, watering, pests, diseases.
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Propagation And Container Growing
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Pitchers (Nepenthes) and Sundews (Drosera)
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Other Important Groups - (e.g. Bladderworts).
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Lesser Grown Varieties of Carnivorous Plants
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Australian Droseras
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Growing and Using Carnivorous Plants
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-in containers, in the ground, as indoor plants.
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Special Assignment
Aims
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Identify different carnivorous plants.
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Describe the cultural requirements for a range of different carnivorous plants
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Propagate a range of different carnivorous plants
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Discuss the identifying characteristics and cultural requirements of several species of both Sundews and Pitcher plants.
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Discuss the identifying characteristics and cultural requirements of several species of both Bladderworts and at least one other genus of Carnivorous plant.
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Describe the identifying characteristics and cultural requirements of several species of less commonly cultivated carnivorous plants.
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Describe the identification and culture of Australian Droseras in depth.
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Determine and describe appropriate ways of cultivating and displaying cultured carnivorous plants.
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Describe one group of carnivorous plants in depth.
How are Carnivorous Plants Classified?
Carnivors are organised by botanists into a number of plant families, as outlined below.
Droseraceae
There are over 150 species in this family, but the vast majority belong to the genus Drosera (i.e. the Sundews). Other genera in the family include Dionaea, Aldrovanda and Drosophyllum. Aldrovanda is an aquatic genus, and all others grow in wetland bogs, both in tropical and temperate climates. Leaves are commonly organised as a basal rosette.
Lentibulariaceae
These are aquatic or bog plants that are more closely related to mint and tomato than most other carnivorous plants (i.e. they are in the same order as Solanaceae and Lamiaceae). Genera in this family may include: Biovularia, Genlisea, Pinguicula (i.e. Butterworts), Polypompholyx (e.g. Pink Petticoat), Utricularia (i.e. Bladderworts).
Sarraceniaceae
Commonly known as pitcher plants, these are plants indigenous to North through to South America. There are three genera: Darlingtonia (e.g. Cobra lily), Heliamphora and Sarracenia (e.g. Parrot Pitcher). They have a pitcher trap similar to Nepenthes, but inside the pitcher, there are hairs that point down which obstruct any insects that get trapped from crawling upwards to escape the pitcher. Leaves develop from a short underground rhizome rather than from an above ground stem. Plants can have a lifespan of between 10 and 30 years.
Byblidaceae
Byblis is the only genus in this plant family. The family is in the same “order” as a number of other carnivorous plants, the most well-known being Pinguicula and Utricularia. Byblis are indigenous to Australia, Indonesia and Papua New Guinea. Most come from warmer climates. B. gigantea and B. lamellata are indigenous to temperate climates of the south west of Western Australia. They normally grow in bogs or marshes, in full or partial sun where temperatures average between 5 and 40°C depending on time of year and species. The plant has two types of glands:
- Sticky glands that occur at the ends of long hairs and exude a sticky mass that catches prey.
- Digestive glands are close to the surface of the stems and leaves.
Common names include Rainbow Plant, Bird Line Trap, or Flypaper Trap.
Cephalotaceae
The genus Cephalotus and species Cephalotus follicularis was discovered in peaty swampland, by Labillardiere in 1806. It is the only known genus and species in this family. It has been known by various common names including the West Australian Pitcher Plant, Pitfall Trap, and the Albany Pitcher Plant.
Originally considered to be closely related to Saxifraga, some older references may list it in the Saxifragaceae family. Modern DNA analysis actually shows that Cephalotus should be in a distinct family of its own, and that the family is in fact more closely related to Oxalis than to Saxifraga.
The plants produce two different types of leaves that grow from underground rhizomes. The normal leaves are flat, hug the ground, last about a year and have no specialised ability to trap insects. When normal leaf growth is well-established, a second type of leaf begins to develop, which bears a trap similar to a pitcher plant. These plants are however not related to pitcher plants. Cephalotus flowers in late summer. The flowers have six petals and six stamens.
Nepenthaceae
Nepenthes is the only genus in this family. There are at least 90 species, though some references may only acknowledge around half that number and others may list over 150. Those that list larger numbers of species may be listing some that are considered to be synonymous names for the same species. Nevertheless, there are many species of Nepenthes, all in the same genus. They are indigenous to parts of Madagascar through tropical Asia.
Common names are Pitfall Trap or Tropical Pitcher Plant.
Dioncophyllaceae
The genus Triphyophyllum is the only carnivore in this family. It is indigenous to rainforests in tropical West Africa.
Bromeliaceae
Many different genera of bromeliads are able to catch plants, but only two (Brocchinia and Catopsis) may be able to digest the animal tissues.
The genus Brocchinia has 5 species, of which at least two are known to be carnivorous. Of the 5 species in the genus occupying lowland savannah and mountain habitats in South America, at least 2 are carnivorous. All species of Brocchinia are indigenous to South America.
The genus Catopsis has 21 species, one of which is carnivorous. Catopsis is indigenous to humid habitats from Florida and the Caribbean, through Central America and into South America.
Others Sometimes Considered Carnivorous
Different people will define carnivorous plants in different ways. Many plants will have adaptations designed to attract insects; or other animals. Often these adaptations function more as a way of facilitating cross pollination and fertilisation of flowers. Sometimes the lure may attract birds that then eat pest insects on the plant.
Other plants (e.g. many rosette forming plants) can trap insects or other animals inside a funnel like rosette of leaves; but one must question whether this is really “carnivorous” if the trap is not accompanied by adaptations to digest the dead animal. Is killing an animal enough, if the plant does not eat it as well?
