Physical characteristics

Hypoxis, a well-known genus of the family Hypoxidaceae, easily recognizable by its bright yellow star-shaped flowers and strap-like leaves. 

Being geophytic herbs, Hypoxis plants overcome winter conditions in the form of an underground rootstock called the corm. Corms are hard, fleshy, mucilaginous and white or yellow-orange within. Sliced corms, when exposed to the atmosphere, turn black with oxidation. In spring, a new set of leaves grows from the apex of the corm. In most species, leaves are arranged one above the other in three rows that radiate outwards. In some species, leaf bases are enclosed in a sheath, forming a false stem. Leaves range from linear to broadly lance-shaped, are hairy in most species and die back over the winter months. Flowering stems appear with the leaves after the first rains in spring. They are unbranched, with 2-12 flowers per stalk. Flowers are symmetrical with 6 tepals, rarely 4 or 8, are bright yellow, giving the genus its common name "yellow stars". Only in two taxa, H. membranacea and H. parvula var. albiflora are the flowers white. The fruit is a capsule that splits across its diameter to expose the small black seeds.

The name Hypoxis is coined from the Greek words hypo meaning below and oxy referring to the pointed base of the ovary or fruit.

Hypoxis flowers are short-lived and are pollinated by solitary and honey bees. Pollen grains in Hypoxis are yellow and are visible through the transparent pollen sacs of honey bees visiting flowers. The fruiting capsule in Hypoxis, called a pyxis, splits along its diameter and the upper portion of the capsule drops off, exposing the black seeds. In a few species such as H. angustifolia, the remaining lower portion of the capsule splits further longitudinally to aid dispersal.

Medicinal uses

This plant has a long history of medicinal use on the African continent and is currently being used in South Africa in primary health care as an immune booster for patients with HIV/AIDS.

Other uses

In the genus, two species, H. hemerocallidea and H. colchicifolia are most sought after for their use in African traditional remedies as well as for preparation of herbal teas and tinctures. This places demand on existing populations of these species in southern Africa and as such, the species are under threat.

The rootstock of Hypoxis is used in various ways in South Africa. H. hemerocallidea and H. colchicifolia rootstocks were used by Zulu traditional healers for centuries in the treatment of urinary infections, heart weakness, internal tumours and nervous disorders. Corms of the latter species are used as an emetic against fearful dreams. The Sotho people use Hypoxis as a charm against lightning and storms. H. argentea has small white rootstocks, and in times of famine the rootstocks are boiled or roasted by the Sotho and Xhosa people as a source of food.

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