33 cactus paintings from the library of Salm-Reifferscheid-Dyck are reproduced in colour as a set for the first time^*, along with a tabulation of probable dates and modern names. Evidence points to Salm-Dyck himself as the artist of most of them, and to around 1805 as the date, when he was a pupil of Redouté. A few later additions are mainly by other hands. Salm-Dyck wrote most of the captions, as is shown from a study of his manuscript notebooks, which are collated here for the first time. Apart from their obvious artistic merit, the paintings are valuable as early illustrations of cacti (columnar cerei mostly) in cultivation in Europe, and as potential lectotypes for Salm-Dyck's names.

The genera Espostoa, Pseudoespostoa, Thrixanthocereus and Vatricania occur in western South America (Ecuador, Peru, Bolivia) and bear prominent lateral cephalia. Because it had been suggested that they should be combined into the single genus Espostoa, their anatomy was studied for clues as to the closeness of their relationships. In general they all resemble each other strongly, and although each has a number of unusual features, each usually shares some of those features with other members of the group so none is truly unique. There is no anatomical basis for maintaining them as separate genera. Many of their unusual features are shared with Weberbauerocereus, Haageocereus, Trichocereus and several related genera, but the anatomy of these groups is not known well enough to be certain of any phylogenetic relationship with the Espostoa group.

A survey is given of all names at specific and subspecific rank that have been published in the genus Ruschia to this date. After the removal of 221 taxa, based on taxonomic studies, 220 species remain in the genus at present. Depending on the state of investigation, a number of species is described and discussed and numerous lectotypes are designated.

The family Cactaceae is widely distributed in South and North America and presents a large spectrum of floral biotypes: melittophily, sphingophily, ornithophily and chiropterophily. The floral biology of Melocactus zehntneri (Br. & Rose) Liietzelb. (subfamily Cactoideae) and Opuntia palmadora Br. & Rose (subfamily Opuntioideae) was studied in a caatinga vegetation, in the district of Alagoinha in Pernambuco, Brazil. M. zehntneri and O. palmadora have tube-shaped flowers, hermaphrodite, without odour, lilac and red respectively. The floral anthesis of O. palmadora is diurnal and the flowers last 48 hours, the nectar is secreted and stored in the nectariferous chamber, and is more copious on the first morning of anthesis (20µl). The sugar concentration of nectar varies between 23 and 30%. Anthesis in M. zehntneri occurs at 14:30h, and the flower remains open even up to 18:30h. The nectar secretion is constant, and is more copious from 15:30h (35µ1), when the visits are more frequent. The sugar concentration of nectar is about 27%. The flowering of the two species overlaps during 3 months, however the peaks of flowering of each species do not coincide. It reduces the competition for the pollinators. The flowers of the two species are typically ornithophilous, and are visited and pollinated by the same species of hummingbird, Chlorostilbon aureoventris. The visits are regular, at intervals of 15 to 30 minutes. The two species are self-compatible.

The family Cactaceae is widely distributed in North and South America, with approximately 1500 species, northeastern Brazil being the the third most important centre of diversity The family is zoophilous, having many groups of animals as pollinators, including bees, beetles, hummingbirds, sphingids, and bats. Pollination by sphingids was observed in a natural population of Cereus fernambucensis Lem. in restinga (coastal sand-dune) vegetation, district of Cabedelo, Paraíba state, NE Brazil. The flowers of C. fernambucensis are white, salver-form, with a long tube (c. 8–15 cm), the expanded perianth-segments forming a bowl shape. Anthesis begins around 23:00h, and at about 02:00h the flowers are completely open. The stamens are numerous and surround the style. Nectar is produced and stored in the nectariferous chamber located at the basis of the flowertube. The average nectar volume is 100 µl, and its sugar concentration is about 24%. The flowers of C. fernambucensis are visited by the sphingid Cocytius antaeus. Visits begin only when the flowers are fully open and last until 04:00h. The interval between visits is 40 minutes. The sphingid alights on the flower and introduces its proboscis into the floral tube, contacting the reproductive organs with the front part of the body and with the tongue. In the morning, from 04:30h, Apis mellifera visits the flowers of C. fernambucensis with regularity, until 06:00h. Although C. fernambucensis is a self-compatible species, the development of fruits was not observed from spontaneous self-pollination. Comparing the results obtained by cross-pollination (85%) with that obtained by hand self-pollination (45%), it is suggested that the xenogamy is the most effective system of reproduction in this species. Comparing the behaviour of sphingids and bees, with the number of developed fruits under natural conditions, it is probable that the flowers of C. fernambucensis use two different classes of pollination vectors: nocturnal visitors (sphingids) and diurnal visitors (bees).

The history, morphology, ecology and conservation status are described of Gerrardanthus tomentosus Harv. ex Hook.f., considered the world's rarest caudiciform species. It is known from only five collections over the past 125 years and from three sites in the Durban area, all endangered by urbanisation and Zulu herb gatherers. Eleven known plants exist within a designated nature reserve, but are undersized and overgrown by alien vegetation. It is a clear candidate for conservation in cultivation, and cuttings and seedlings are being successfully raised.

The rich succulent flora of the rarely visited Epupa Valley between Namibia and Southern Angola includes one newly described endemic succulent, Euphorbia leistneri, and at least 8 other protected species. The area is scheduled as a reservoir for a hydroelectric power plant. The impact of this on the Himba people who inhabit the valley and on its flora is assessed.

A note on the publication dates of two seminal works by Backeberg is contributed by Roy Mottram. The alphabetic index of Opuntia names is continued from Bradleya 16: 119–136. 1998. It includes a new combination for Opuntia inaequilateralis var. angustior (Ritter) Crook & Mottram, a new status for Opuntia kleiniae ‘Cristata,’ and eight new typifications.

References to lists of literature on succulent plants and to articles dealing with bibliographical details of individual publications are presented. Also listed are articles on finding and collecting literature.