Pitcher plant: Encyclopedia II - Pitcher plant - Types of pitcher plant

Pitcher plant - Types of pitcher plant

The families of Nepenthaceae and Sarraceniaceae are the best-known and most speciose groups of pitcher plants.

The Nepenthaceae contains a single genus, Nepenthes, containing about 70 species and numerous hybrids and cultivars. In these Old World pitcher plants, the pitchers are borne at the end of tendrils that extend from the midrib of an otherwise unexceptional leaf. The plants themselves are often climbers, accessing the canopy of their habitats using the aforementioned tendrils, although others are found on the ground in forest clearings, or as epiphytes on trees.

In contrast, the New World pitcher plants (Sarraceniaceae), which comprise three genera, are ground-dwelling herbs whose pitchers arise from a horizontal rhizome. In this family, the entire leaf forms the pitcher, whereas in the Asian pitcher plants, the pitcher arises from the terminal portion of the leaf. The species of Heliamphora, which are popularly known as marsh pitchers (or erroneously as sun pitchers), have a simple rolled-leaf pitcher, at the tip of which is a spoon-like structure that secretes nectar. They are restricted to areas of high rainfall in South America. The North American genus Sarracenia are the trumpet pitchers, which have a more complex trap than Heliamphora, with an operculum, which prevents excess accumulation of rainwater in most of the species. The single species in the Californian genus Darlingtonia is popularly known as the cobra plant, due to its possession of an inflated 'lid' with elegant false-exits, and a forked 'tongue', which serves to ferry ants and other prey to the entrance of the pitcher. The species in the genus Sarracenia readily hybridise, making their classification a complex matter.

There are two other genera of pitcher plants, but both contains just one or two carnivorous species.

The Cephalotaceae is a monotypic family with but one genus and species, Cepahlotus follicularis. This species has a small (2 to 5 cm) pitcher similar in form to those of Nepenthes. It occurs in only one location in southwestern Australia.

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 that many collect detritus, it is not surprising that a few should have been naturally selected to develop the habit into carnivory by the addition of wax and downward-pointing hairs.

Adapted from the Wikipedia article "Types of pitcher plant", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki