We provide an overview of the taxonomy, ecology, and biogeography of the epiphytic cacti of Bolivia, which is second only to southeastern Brazil as a centre of epiphytic cactus diversity in South America. Twenty-one obligatory or facultative epiphytic species with 2 varieties in 7 genera occur in Bolivia. A further 14 species in 6 normally terrestrial genera are recorded as accidental epiphytes. Two taxa are described as new: Lepismium asuntapatense sp. nov. M. Kessler, P.L. Ibisch & Barthlott and Rhipsalis baccifera ssp. nov. cleistogama M. Kessler, P.L. Ibisch & Barthlott. Eight species are endemic to Bolivia, mostly in humid montane forests. Preliminary ecograms and extrapolated range maps for all obligatory epiphytes are provided. GIS-overlay of the range maps is used to predict the species diversity patterns for all obligatory epiphytes and for the genera of Rhipsalideae. Species-richness is highest in humid montane forests, but physiognomically and in relation to overall species-richness of vascular epiphytes, epiphytic cacti are most important in semi-humid montane forests of inter-Andean valleys and the Chaco zone. Three species are classified as vulnerable and all others as not endangered.

During numerous expeditions to the Western and Eastern Cape Provinces of South Africa, a number of Bulbine species encountered were investigated. After research and consideration of available information and examination of herbarium material in the Bolus and Compton Herbaria, it was decided that four species were as yet unnamed. These new species, Bulbine undulata G. Will., B. rupicola G. Will., B. muscicola G. Will, and B. canaliculata G. Will, are described. Observations on climate, habitat and associated plants are included. The growth habit related to their environmental niches is discussed and where appropriate the new species' closest affinities are commented on. An accurate line drawing has been included for each species showing all-important morphological features coupled with several colour plates. All the new species possess interesting leaves and three occur under extreme climatic conditions in close association with other succulent plants.

On the basis of seed morphology, Echinocactus mandragora Berger is seen as unrelated to Turbinicarpus, but a closer ally of Sclerocactus, Echinomastus and Pediocactus. It differs from these genera in its floral and fruit morphology, therefore we propose a new genus, Lodia Mosco & Zanovello, to accommodate this species.

A phenetic analysis of the genus Thelocactus is presented. The collected data, 65, and the 34 Operational Taxonomic Units used for the study were processed by a principal components analysis method. The ordinations made lead us to conclude that Hamatocactus setispinus is not congeneric with Thelocactus from which it has to be separated. Some nomenclatural changes are also made in order to adjust the taxonomy of the genus to the results obtained.

A new species of Raphionacme, R. ernstiana, is described and illustrated. The Tanzanian endemic is regarded to be closely related to R. hirsuta and R. madiensis.

Based on studies in more than 700 populations of Drosanthemum, the capsule morphology is described, and thirteen fruit types are distinguished. For 66 of the 108 accepted species, coloured figures of the capsules are presented. All names ever published in Drosanthemum are given and D. deciduum is described as a new species, D. subspinosum as a new combination; for many species, lectotypifications are presented.

The alphabetical index of Opuntia names is continued from Bradleya 17: 109-131.1999. Includes fourteen new typifications (9 LT, 4 NT, 1 ET), two new cultivar names, and eight new cultivar standards.