The Cherangani Hills lie in N. W. Kenya, flanked by the Trans-Nzoia and Mt. Elgon to the west, and to the east by the Eastern Rift Valley, of which they form the Marakwet escarpment above the Kerio Valley (Fig. I). They are composed of metamorphic rocks with conspicuous quartzite ridges and occasionally marble veins, unlike the other Kenyan Highlands which are relatively recent volcanics. The Cheranganis reach to little under 12,000' (c. 3,600 m) at Chemnirot in the north-east, but it is because of their relatively low altitude when compared with these others that Hedberg (1951) omitted them from his studies on the vegetation belts of the East African mountains. Although considerable collections of herbarium material have been made (see Hedberg, 1957), there are few published accounts of the vegetation of the Hills. In their paper on the Giant Groundsels, Cotton and Blakelock (1937) descriptionbed the swampy areas of the north-east from I. R. Dale's notes; Jeannel (1950) outlined the associations of the secondary grasslands of the south-east, but, apparently unaware of Cotton and Blakelock's work, stated that there were no Giant Groundsels in the Hills. Unwin-Heathcote and Carson (1951) descriptionbed the vegetation of the south-western area through which the 'Cherangani Highway' was built.