By Agustin Franco, Ph.D., Sydney, N.S.W., Australia
This article is dedicated to those who spend their lives growing this beautiful, but unusual carnivorous plant. Cephalotus follicularis (labillardiere, 1806), commonly known as the West Australian pitcher plant, Albany pitcher plant or Australian ground pitcher, is the only species of the genus Cephalotus. The word “Cephalotus” comes from the greek “kephalotos” meaning "headed", which refers to the filaments of the stamens. The word “follicularis” refers to follicles or small sacs, which describes the shape of the carnivorous pitchers [Fig. 1]. [pic]
Fig 1. Cephalotus follicularis in the wild. (Photo courtesy of Mrs. Pat Johns, Wildflowers Society of Western Australia) The plant’s original habitat is Southwestern Australia, its range of distribution is about a 400 km strip from regional Albany to Eusselton (Western Australia). This plant naturally grows in a meso-mediterranean climate characterized by cool and wet winters followed by hot summers. However, the temperature fluctuations in this area almost never reach below 5ºC in winter and hardly exceed 25ºC in summer, but it can rise up to 40ºC (Cheers, 1992) As most carnivorous plants, it prefers a humid environment and loves to grow amongst grasses and shrubs. In other words, it prefers shaded areas. If the plant grows under direct sunlight, it accumulates anthocyanin, a pigment responsible for the red colouration of the pitchers. In nature, Cephalotus mainly grows in a mixture of sand, grass, and peat while dieting on mainly crawling insects such as ants. Cephalotus follicularis has two types of leaves: non-carnivorous and carnivorous. The non-carnivorous leaves are usually spear-shaped; even though, during the winter, round non-carnivorous leaves are produced. The carnivorous leaf or pitcher is one of nature’s masterpieces. It has a peristome or mouth filled with inner pointing teeth. The lid has translucent segments alternating with darker ones and has three functions: The first one involves attracting insects by showing the reflection of the water at the bottom of the pitcher through its semi-transparent segments. The second function is to keep the rain-water out of the pitcher; and the third function is to maintain the internal humidity in hot days, by superimposing over the mouth of the pitcher. As the levels of humidity return to normal, the lid would move back to its original position. The outer walls of the pitcher have a T-shaped central rib with hairs along the sides and two lateral ridges also with hairs that serve as ladders for the insects attracted by the sweet nectar contained within the pitcher. The mouth or peristome has around 24 inward pointing teeth (Lloyd, 1976) . Mature pitchers have these teeth of up to 4mm long in the center of the mouth, while other varieties with similar size pitcher have smaller teeth of up to 2.5 mm long. The inner wall of the pitcher is coated with wax creating a very slippery surface. The inward pointing teeth, in combination with the slippery inner surface of the pitcher, makes any insect’s attempt to escape futile. The lid also varies in shape. While some Cephalotus have an inverted spoon-shaped lid, others have a half shell-shaped lid. The pitcher is filled with bacteria and digestive enzymes, which will break down and absorb proteins and other nutrients from the prey. (Lowrie, 1998). There are some variations in the shape of the pitcher as well. The most common pitcher type has an elliptical-shaped mouth. There is another variety with a very narrow and cylindrical mouth and a sausage-shaped pitcher. This variety of Cephalotus produce fairly long pitchers (up to 5 cm long) and wide non-carnivorous leaves (Phill Mann’s collection). One of the most interesting topics amongst carnivorous plant growers is Cephalotus follicularis pitcher size. The “typical form” of Cephalotus...