Tuesday, 13 October 2015

Albany's pitcher plant like no other


In near coastal swamps from Albany west to the Indian Ocean, you might find one of Australia's four species of pitcher plant. In August this year I didn't, despite being given some pretty precise instructions by local botanist Professor Steve Hopper. Instead I spent a pleasant hour or two photographing a few of the other species that frequent this coastal wetland, such as Bridal Rainbow (Drosera macrantha, a sundew), Southern Cross (Xanthosia rotundifolia in the carrot family) and the Albany Daisy (Actinodium ?cunninghamii, in the myrtle family rather than a true daisy).


The pitcher plant familiar to most of us is the Nepenthes, usually a scrambling or climbing tropical plant with 'pitchers' formed at the end of a tendril extending beyond a typical looking leaf. Three species occur in the far north-east tip of Australia (Cape York), an extension southwards of a genus mostly found in South-east Asia.

The trumpet pitchers, Sarracenia and its relatives in North America and the top of South America, convert an entire leaf into a pitcher. They grow on the ground, mostly looking like elegant tall vases, or trumpets.

The third kind is Cephalotus, with inner leaves typical and outer leaves adapted into pitchers. It only grows in the far south-west corner of Australia, in those aforementioned swamps. According to Steve Hopper and Paul GioiaCaphalotus is a 'highly divergent relict of a rainforest lineage'. 

These three different kinds of pitcher plants are not at all closely related, each responding independently to poor boggy soil by producing an insect catching and digesting trap to extract nutrients from hapless visitors. A few other plants, such as bromeliads, are thought to deliberately catch insects in a similar way, and there are 580 or so species in 20 genera and 12 different plant families that have a carnivorous life style of some kind.


Cephalotus means 'with a head' referring either to the lid on the pitcher or more likely the swellings on the male-bearing structures above (the stamens with their yellow anthers); it's an evocative name, as evidenced by it being taken up by a death metal band from Tokyo. There is only one species, Cephalotus follicularis, with the species name meaning 'little sacks', a certain reference to the pitchers.

The Albany Pitcher Plant was probably first seen by botanists in 1791, when collected by Archibald Menzies. The species wasn't formally described and named until 15 years later, after French biologist Jacques-Julien Houtou de Labillardi√®re examined material brought back to Europe (via Java and England) collected by Jean Baptiste Leschenault de la Tour on the expedition to Australia led by Nicolas Boudin. Although I do note David Mabberley, in his The Plant-Book, says it was discovered by Robert Brown in 1801.

As with the the other plants mentioned here, the pitcher acts as a 'pitfall trap' for insects and other small prey (the Cephalotus traps are at most 6 cm across). Nectar is the attractant and the slippery upper ridge with downward pointing teeth means once inside the insect struggles to escape (the lid is more to keep rainfall from diluting the digestive soup inside than to stop anything getting out).

It's odd that we should have two quite different kinds of pitcher plants at two extreme ends of Australia, almost as far from each other as possible. But then it's a odd country with an often odd flora and fauna. The odd things often tell us a little about our country's cultural and natural history.

Images: Images of the Albany Pitcher Plant are by Barry Rice, from the International Carnivorous Plant Society pages. The other images are from hour or two wandering around likely habitat.

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