Nearly 4 years ago, on 6 March 2006, we selected from our Flickr Pool a photo of Swainsona formosa for Botany Photo of the Day. Heather from Adelaide, Australia took that picture, the entry for which you can access here. Today, we feature a lovely specimen of S. formosa that left Australia and made its way across the Pacific to the small greenhouse behind our shop.
Like the other Australian plant featured on Botany Photo of the Day this week, Daviesia rhombifolia, Swainsona formosa is a member of Fabaceae. The species is easily distinguished by the deep-red petals of its clustered, spring- and summer-blooming flowers, and by the typically black centre (or boss) around which these petals are arranged. Plants' main stems—which, in certain areas (the Pilbara region), reach to a height of around 2 metres—put forth spirally arranged pinnate leaves of pale green, while on the lateral stems the leaves are arranged in two opposite rows. The species' sexual apparatus, which is hidden by the keel, consists of 10 stamens (9 of which are joined and one of which stands free) and a single ovary. The fruit is a legume that contains about 50 seeds, and in the wild birds are the species' primary means of propagation. In terms of its appearance, S. formosa—which thrives in arid desert habitats—is fairly distinct amongst its relatives, which include the white-keeled 'marginata' and the pink-bossed 'elegans' cultivars.
The botanist George Don named the genus Swainsona in honour of Isaac Swainson, the 18th and early 19th century owner and operator of a large botanical garden in Twickenham, England. Specimens were first collected in the late 17th century by the botanist William Dampier, and the common name honours the explorer Charles Sturt, who reported having seen large quantities of the plant while on expedition in 1844.
A reclassification of the species as Willdampia formosa was proposed in the last years of the 20th century, but the suggestion was generally rejected by the scientific community. The species is the adopted emblem of South Australia, and it is frequently featured in visual and verbal art. Though the plant is notoriously difficult to grow, ambitious gardeners should know that some have had success when treating specimens as annuals, and when growing them in deep containers exposed to full sun.
This is my final entry of the summer. I would like to express my gratitude to you all for your helpful contributions, which made of this daily responsibility an unalloyed pleasure. The site seems to me a genuine celebration of curiosity and learning, and I hope that it continues to thrive in the coming years, perhaps through each of you extending its general mood out into other arenas of contemporary social life as well.