The taxonomic significance of trichome type and distribution in Melolobium (Fabaceae)

All species of Melolobium Eckl. & Zeyh. were examined for epidermal features and particularly the glands which are a distinctive feature amongst the southern African Genisteae. For comparative purposes, three species of Argyrolobium Eckl. & Zeyh., all five species of Dichilus DC. and five species of Polhillia C.H.Stirt. were also examined for trichome type and distribution. Three trichome types are recognized in Melolobium. Trichome type and distribution provide an important insight into taxonomic relations at species level in Melolobium and sometimes even allow a distinction between regional forms. The distribution of glands (sessile and stalked) is of considerable diagnostic value in identifying species of Melolobium. A key to all the species of the genus based mainly on type and distribution of trichomes, is presented.