Geissorhiza is a large genus of around 84 perennial species, of small to medium corm bearing plants in the Iridaceae family found in the winter rainfall region of the south and west coasts of southern Africa. Many of them make very handsome container plants and benefit from extra water during growth. The name Geissorhiza is derived from the Greek words geisson and rhiza which mean tile and root respectively. This is in reference to a tunic which covers the corms like a roof tile. The bulb-like structure is used as a storage organ during the dormant period. It is closely related to the genus Hesperantha, the main difference being that most Hesperantha are night bloomers.

Geissorhiza subrigida, commonly known as Rush Satin, is a rare and critically endangered South African endemic species found in the Northern Cape province growing on the Bokkeveld Mountains near Nieuwoudtville. It occurs in dry montane fynbos in rocky soils derived from sandstone, flowering well after fire. It has rush-like leaves and from late winter to early spring it bears gorgeous blue to purple flowers.