An account is given of the life and literary career of N. J. Jacquin (1727–1817), ‘the Linnaeus of Austria’, with particular attention to his publications on the Stapelieae (Asclepiadaceae). A portrait of Jacquin and colour reproductions of two of his plates are included.

A new species of Euphorbia from southern Ethiopia, E. gymnocalycioides, is described. A history of the specimens cited is given, together with topographical details. Its relationship with E. turbiniformis, and of both species with section Euphorbia of the genus, are discussed. The homology of strange structures in the tubercle axils is suggested.

A new combination Huernia longii subsp. echidnopsoides (Leach) Bruyns is made for what was previously known as H. pillansii subsp. echidnopsoides Leach. Reasons are put forward to justify this alteration.

A systematic treatment of Ferocactus Britton & Rose sensu stricto is presented. Following guidelines outlined in an earlier paper (Taylor & Clark, 1983) the species comprising subg. Ferocactus are arranged in two sections and four informal groups. In total 23 species and 20 heterotypic infraspecific taxa are included, with their authorities, places of publication, types, essential synonyms and distributional data. Brief diagnostic descriptions are provided to supplement the key to species and to enable identification of infraspecific taxa. References to good published illustrations are cited as an additional aid to recognition.

A commentary is provided in tabular form on 24 taxa of Cactaceae enumerated by Plumier in his manuscript ‘Botanicum Americanum’, together with half-size reproductions of copies at Kew of 21 of his drawings. Early names for Plumier taxa whose identity or status requires confirmation could affect the currently accepted names of species in several genera.

This is the second instalment of an annotated index of Mammillaria names, continued from Bradleya 1: 105–128 (1983). The series-name Macrothelae is replaced by Mammillaria in accordance with Art. 22.1 of the 1983 (Sydney) edition of the International Code of Botanical Nomenclature. The species M. heidiae is transferred to subg. Mammillaria ser. Ancistracanthae.