Plant 126

Lysichiton americanus Hultén & H.St.John (Araceae)


American skunk cabbage

Lysichiton americanus is a distinctive species whose distribution, scent and appearance are captured by its common name. The American skunk cabbage's native range is restricted to the northwestern North America. It occurs in shaded forests, exposed swamps and even running water; the essential attribute is its habitat must be wet. The species is well adapted to growing in low-oxygen conditions. The tiny flowers are crowded into phallus-like spikes (spadix) surrounded by a large, chrome-yellow bract (spathe). It flowers early in the year before the leaves, and the spadix emits an unpleasant, faeces-like, indole-rich scent. The spathes quickly wilt, which is the origin of the name Lysichiton, and are followed by large, shiny leaves.

In its native range, Lysichiton americanus is pollinated by adult rove beetles that feed on pollen and use the spadices as mating sites. The plant's distinctive scent attracts the beetles, which then search for the yellow spathe. Unlike many of members of the family Araceae, the spadix of Lysichiton does not heat up to attract insects. Lysichiton flowers are hermaphrodite but the spathe is strongly protogynous, that is the flowers are first functionally female and then functionally male. Consequently, individual plants have male and female phases. Adult plants begin to set seed after about five years.

Seeds are the primary way the plant propagates itself. They fall from the withered spadix and germinate close to the parental plant or are dispersed by water when the parent's habitat floods. In its native habitat animals have an important role in seed dispersal; no such observations have been made in Europe.

Lysichiton americanus has been grown as an ornamental curiosity in Britain since the early twentieth century. Given its hardiness, and the ease with which it sets seeds, it is hardly surprising Lysichiton forms naturalised populations in parts of southern and western Britain and mainland Europe. In Germany, American skunk cabbage has been reported to be responsible for the local extinction of plants such as Carex echinata and Viola palustris.

The genus contains one other species, Lysichiton camtschatcensis, which is native to north-east Asia. The two species are very similar to each other and are most easily separated by the foetid flowers and yellow spathes in Lysichiton americanus and scentless flowers and white spathes in Lysichiton camtschatcensis. In cultivation the two species hybridise which has led to the suggestion they might best be considered subspecies of a single disjunct species.

Further reading

Pellmyr O and Patt JM 1986. Function of olfactory and visual stimuli in pollination of Lysichiton americanum (Araceae) by a staphylinid beetle. Madroño 33: 47-54.

Willson MF and Hennon PE 1997. The natural history of western skunk cabbage (Lysichiton americanum) in southeast Alaska. Canadian Journal of Botany 75: 1022-1025.

Stephen Harris