Star flower

Description:

The name Spiloxene is derived from the Greek spilos, a spot, and xenos, a host or a stranger, which emphasizes the dark spots commonly found in the centre of the flowers of the widespread and well-known S. capensis. Spiloxene is a relatively uniform group of small, deciduous plants which seldom reach a height of 500 mm. The rootstock is a corm which is replaced annually after each growing season. Most often the desiccated corms of the previous seasons persist for a year or more in a vertical series. Each inflorescence consists of a slender, leafless scape which terminates in a few, often inconspicuous bracts and one or two (rarely up to seven) flowers with long, slender pedicels. As is typical in the family Hypoxidaceae, the flowers have six tepals, six stamens, a three-chambered, inferior ovary, and a three-branched style. Flowers are uniformly star-shaped and mostly golden or pale yellow in colour, but in a few species they are white and rarely pink. Distinct red and green stripes often line the backs of the outer tepals in species such as S. capensis and S. canaliculata, however, most often the backs of the outer tepals are plain reddish pink or green. The largest and most striking flowers are those of S. capensis and S. canaliculata which also have dark spots or 'eyes' at the base of the tepals. In S. capensis the spots are generally blackish and occasionally iridescent blue-green, whereas those in S. canaliculata are deep, matt purple.

Habitat:

Spiloxene has about 25 species, several of which are yet to be formally described. As presently understood, the genus is confined to areas of southern Africa experiencing rainfall in winter or throughout the year. Eighteen species are found in Western Cape, eight species are known from Northern Cape and three species come from Eastern Cape. They range from the coastal forelands to high altitudes on the Cape Fold Mountains and the inland escarpment. Habitats are mostly seasonally damp sites such as seasonal pools, seepage areas, stream banks, and wet rock ledges. The recently described S. pusilla, with its delicate, pale green leaves and minute flowers, shelters in deep recesses below overhanging rocks.

Notes:

Like all Hypoxidaceae the flowers of Spiloxene have no nectaries; therefore the only reward to visitors is pollen. Nevertheless, the open, star-shaped flowers have prominently exposed anthers which are well suited to attract pollen-collecting insects that lack specialized foraging behaviour. The main pollinators are thought to be bees. Spiloxene capensis and S. canaliculata, however, belong to a species-rich guild of Cape plants that have flowers with dark, central markings which hopliine (Scarabaeidae) beetles use as visual cues to locate pollen and as suitable sites for mating. Because of the importance of pollen as an attractant, it is quite possible that the closing of Spiloxene flowers under unfavourable conditions minimizes the loss of pollen which, unlike nectar, is not a resource that can be renewed.