Carnivorous Plant Encounter, Walpole, WA
Robert Gibson
10/13/2001

Carnivorous Plant Encounter, Walpole, Western Australia


Robert Gibson

    In late December 1996 I spent 3 days travelling around the south coast of Western Australia, observing 15 species of carnivorous plants in the wild whilst bushwalking. The plants seen, around Nannup, Northcliffe and Walpole, included many I have found elsewhere on the south coast as well as a few surprises; including Drosera binata, D. hamiltonii and Utricularia simplex. Following is account of the carnivorous plants encountered.
Cephalotus follicularis
                    The Albany Pitcher Plant was seen at two sedge swamps either side of Walpole. A third location, near Pemberton, was visited but was too overgrown to be deemed safe for exploration. At the sedge swamp west of Walpole the pitcher plants grew on the upper slope of the swamp, often at the foot, or the pedestals, of a distinctive, and robust species of Gahnia "grass". This sedge has grey green leaves with coarsely serrated margins and smooth scapes, to 2.5m tall with flowers enclosed by a pair of large bracts. The height of vegetation in this swamp, which included many species of Myrtaceae, varied from 0.8 to 3m, and it appeared to have been burnt in the last few years.
                    Clumps of Cephalotus varied in appearance from fully green, with an equal production of pitchers and non-carnivorous leaves, to striking clumps of pitchers, to 5 cm tall, with abundant red pigmentation on the interior and exterior of the pitchers, in which the translucent "windows" on the lids appeared as vibrant white stripes. The contents of one pitcher examined consisted primarily of the recognisable remains of dark brown ants, to 6mm long, a species which lives in the sedge swamps. The remains of scapes were found of some clumps indicating flowering the previous summer.
                    At this site, in damp peaty soil, Cephalotus grew in the company non-flowering Drosera hamiltonii, D. binata and D. pallida. It was interesting that no pygmy Drosera nor Utricularia grew in this section of the swamp.
                    The second site, consisted of carbonaceous shale and sandstone cliffs at the back of a narrow beach, over which fresh water was constantly seeping. The pitcher plants grew on unstable slopes, the surface 30cm of which periodically slipped downslope leading to the death of all plants on board through desiccation or immersion in salt water. Many of the pitcher plants here were in scape, which grew to 60cm tall and varied in the level of flower development, although no flowers were open at the time. A well-formed rosette of non-carnivorous leaves precedes the emergence of a scape at a growing point.
                    The pitchers grew to 3cm tall and were generally brightly red pigmented in response to exposure to the sun. The contents of one old pitcher examined proved to be a soup of unrecognisable invertebrate body parts as well as 3 white, very healthy, living, worm-like dipteran larvae. The only variation observed in the plants at this site was the presence or absence of stipules on the lower third of the scape. At this coastal site Cephalotus grew with pink petalled plants of Drosera pulchella.
Drosera binata
                    Drosera binata was found on the edge of a sedge swamp near Broke Inlet, west of Walpole, growing with Cephalotus follicularis, D. hamiltonii and D. pallida. The plants had one to five olive green, erect, self-supporting petioles to 20cm tall and supported a singly forked lamina to 6 cm long. The lamina, with fully dark red ret