Pitcher plant

Pitcher plants are carnivorous plants featuring a deep cavity filled with liquid. Insects such as flies are attracted to this cavity. The sticky liquid traps and gradually dissolves the body of the insect, transferring its minerals to the plant. Like all carnivorous plants, they occur in locations where the soil is poor in minerals and/or too acidic for most plants.

Groups

The families of Nepenthes and Sarracenia are the best-known and most speciose groups of pitcher plants, and within each genus species will readily hybridise, making classification and indentification a hard task.

Other pitcher plants include:

• Cephalotaceae, a monotypic family with but one genus and species, Cephalotus follicularis. This species has a highly-developed pitcher (a few centimeters at most) but occurs in only one location.
• The Heliamphora, another small, very geographically limited family. They have a simple looking pitcher, like a leaf curled round on itself, with a spoon-like structure at the end. They are yet to be studied in detail in their natural habitat, so it is not know what function this performs.
• Darlingtonia are closely related to the Sarraceniaceae, though they have a hood over the top of their trumpet, rather than a flap.
• A few species of bromeliads Bromeliaceae, such as Brocchinia reducta and Catopsis berteroniana are known or suspected to be carnivorous. Bromeliads are monocots, and given that they all naturally collect water where their leaves meet each other, and many species are epiphytic and collect detritus (the tank bromeliads), it is not surprising that a few should have developed the habit a bit further into carnivory by adding wax and downward-pointing hairs.

Localities

Pitcher plants occur in a very discrete set of locations around the world.

• Sarracenia grow along the Eastern seaboard of North America. (Sarracenia purpurea is the official flower of the Province of Newfoundland and Labrador, Canada).
• Nepenthes occur only in South East Asia and Madagascar, and especially in high mountain locations where the climate is cooler and wetter than the surrounding tropical lowlands, for example Mount Kinabalu, Malaysia and Lake Toba, Indonesia. Many species are endemic to particular mountains.
• Cephalotus is native to a very small area in the south-west of Australia, around the town of Albany.
• Heliamphora grow only on the Tepuis of Southern Venezuela and Northern Brazil.
• Darlingtonia occur in the North-West United States, mainly the states of Oregon and California.

Structure

It can be seen from the list above that pitcher plants can be loosely spilt into two groups, American and Asian. American pitcher plants are very different in appearance and structure to the Asian plants, American plants consisting of simple trumpets growing straight from the ground (from rhizomes), and Asian plants growing as a vine and having highly developed pitchers and several life stages.

Reference

• Juniper et al., The Carnivorous Plants, London: Academic Press, 1989.

External Links

• Andreas Wistuba, collector of all kinds of pitcher plants