A new semi-succulent species of Euphorbia (Euphorbiaceae), E. erythrocucullata, is described from SW Madagascar. The taxon is placed in the subgenus Lacanthis Raf. and grouped with E. pedilanthoides Denis; placement in this group is discussed.

Hylocereus undatus (Haw.) Britt. & Rose subsp. luteocarpus Cálix de Dios is proposed as a new taxon from the dry deciduous forest of the Yucatan Peninsula. The new subspecies is described, illustrated, and its affinities discussed. It differs from H. undatus subsp. undatus by the presence of hairs in the areoles, greater number of spines, and yellow versus red fruit.

Columnar cacti can be pollinated by various insect and vertebrate species, often showing either close adaptations to a single pollinator group, or a mixed pollination syndrome, depending on a variety of different animals for pollination. As pollination data for columnar cacti in South America are scarce, we investigated the spectrum, frequency, and behavior of floral visitors in Echinopsis atacamensis subsp. pasacana. We compared two habitats with differences in mean annual precipitation and human impact, finding considerably higher activity and diversity of flower visitors in the population with higher humidity. Bees, wasps, and the giant hummingbird (Patagona gigas) were shown to visit cactus flowers during the day to gather nectar or pollen. We found marked differences in the spectrum of floral visitors between both populations. In one study site, the introduced honeybee Apis mellifera removed large quantities of pollen, but seemed to be a comparatively inefficient pollinator. Additionally, first evidence for visits by nocturnal hawkmoths is provided. These results demonstrate an unspecialized floral syndrome for Echinopsis atacamensis subsp. pasacana, with both diurnal and nocturnal pollinators. Such a mixed floral syndrome is fairly widespread among columnar cacti in the northern hemisphere but was hitherto only shown for one South American species, Weberbauerocereus weberbaueri.

Leaf anatomy of Conophytum–a genus of 100 species of miniature xerophytic plants from the succulent Karoo in southern Africa–was examined using thin sections of plastic-embedded tissue and bright-field and polarized-light microscopy. Eighty-four species, from all recognized sections of the genus, were sectioned using material of known wild origin, with many species represented by multiple infraspecific taxa or populations. The broad scope of this investigation permits, for the first time, a meaningful study of the comparative anatomy of this large, morphologically diverse genus. The distribution of anatomical characters is described including: the pattern of deposition of calcium oxalate crystals in the epidermis, the presence and number of layers of hypodermis, and the presence and shape of tanniniferous idioblasts in the mesophyll. Typically xeromorphic characters like a hypodermis and epidermal crystal layers tend to be reduced or absent in species from sheltered niches, including soil-embedded, subterranean species with windowed leaves. Embedded species also frequently lack tannin cells, perhaps because their growth form reduces the need for chemical defenses against herbivores.

In this paper I present a cladistic evolutionary hypothesis for 83 taxa of Conophytum, a genus of leaf-succulent xerophytes endemic to South Africa and Namibia. My analysis is based primarily upon anatomical and micromorphological characters. The genus as a whole, and some of its traditional sections such as Ophthalmophyllum and Pellucida, is shown to be monophyletic, with bootstrap support, though many other branches are not well supported. Within Conophytum, nocturnal flowering and the embedded window-plant life form appear to have originated several times in separate lines of evolution. The most basally-diverging lineages in the genus are native to the Richtersveld in northern Namaqualand, suggesting an origin in that area. A trend towards the loss of anatomical adaptations to drought, such as sunken stomata, and the gain of adaptations in gross morphology, such as growth embedded in soil, is evident in many of the more recently derived lineages.

The genus Bergeranthus Schwantes comprises ten species of leaf-succulent Aizoaceae centered in the Albany Center of Floristic Endemism and restricted to the Eastern Cape Province of South Africa. No taxonomic revision of the genus or key to its species has been undertaken until the present study. Three species are reduced to synonymy and two new species, B. albomarginatus and B. nanus, are described. Existing species descriptions are augmented and all species are illustrated. A key to the species is provided.

Echeveria andicola Pino, a new species endemic to central Peru, is described. Although fairly common in the departments of Junín, Pasco and Huánuco, the plants had formerly been identified as E. chiclensis or E. peruviana; however, careful analysis supports the recognition of these plants as an unpublished species. A comparison with other similar species of the area is presented.

A new species and three new varieties of Peperomia from northern Perú are described. Three of them are plants collected and named by Paul Hutchison but never published. Peperomia columnaris looks like an erect-growing variety of P. nivalis, but its inflorescences and fruit structure suggest it is closer to P. ferreyrae and P. columella. Peperomia dolabriformis var. grandis is similar to the type variety, but is generally bigger, glaucous green with clearly petioled leaves and prominent lateral nerves. Peperomia cymbifolia var. goodspeedii is a compact, dwarf variety of this recently described species, purplish and with conspicuous red leaf margins. Peperomia macrorhiza var. lilliputiana is a variety of this geophilous species with miniature succulent cordiform leaves, densely crowded and almost covering the upper surface of the tubers.

Fifty species of Opuntioideae were examined to establish 1) the range of anatomical variation occurring in this subfamily, 2) characters these plants share with other desert-adapted plants, and 3) information about phylogenetic relationships within Cactaceae. Only three characters are universally present in stem-photosynthetic, stem-succulent plants: 1) a persistent epidermis, 2) a thickened cortex, and 3) a palisade cortex. A multiseriate hypodermis with extremely thick walls and crystals is almost universally present in Opuntioideae and Cactoideae but is not uniformly present in non-cactus succulents. Opuntioideae lack many features common in Cactoideae: they have no extremely thick cortex, no extensive system of cortical bundles, no collapsible cortex cells, and no medullary bundles. Features common to Pereskia, Cactoideae and Opuntioideae, which may be relictual in the family, are 1) a tendency to form multiple epidermis, 2) a multiseriate, thick-walled hypodermis with druses in at least one layer, 3) mucilage cells, 4) an unvascularized cortex (Blossfeldia in Cactoideae), 5) phloem fiber caps, 6) fibrous wood, 7) narrow rays, 8) scanty paratracheal parenchyma, 9) an unvascularized pith (some Cactoideae have medullary bundles), and 10) indeterminate growth (Pereskiopsis in Opuntioideae). Within Opuntioideae, Pereskiopsis has the greatest number of these characters; it may most closely resemble the ancestors to the Opuntioideae.

E. Yale Dawson's early passion for cacti continued into his professional career as a marine botanist studying seaweeds. He produced important floristic, taxonomic and biogeographic accounts of seaweeds, primarily in the N. E. Pacific. In 1963, the Botanical Society of America awarded him the Darbaker Prize for his magnum opus, The Marine Red Algae of Pacific Mexico, published in eight parts. Dawson also made many important observations on the distribution and abundance of cacti, collected and described several new taxa, and did much to enhance layperson interest in the biology and horticulture of these plants. For his contributions to the study of desert plants, the Cactus & Succulent Society of America made him a Fellow. He was also a member of the International Organization for Succulent Plant Study.

Eric Walther classified three generally epiphytic species in his series Spicatae of Echeveria. Two of these, E. rosea (n = 34) and E. pittieri (n = 62) are distinctive, but E. chiapensis is not distinguishable from E. rosea. Certain plants from Oaxaca and Veracruz closely resemble E. rosea vegetatively but differ in the form of their flowers, and they have n = 51 or 50 1. We describe them here as a new species, E. tencho. All three species hybridize readily with many other Mexican Crassulaceae in cultivation.

Although we first thought that E. rosea was a tetraploid and E. tencho a hexaploid having a common ancestor with n = 17, analysis of chromosome pairing in their hybrids with other species requires a different interpretation. At meiosis in its hybrids none of the 34 gametic chromosomes from E. rosea can synapse with any of its others, although many synapse with parts of one or more chromosomes from the other parent. They are all different, and, like many other Mexican Crassulaceae that have this many chromosomes, E. rosea is effectively diploid. The behaviour of the 50 or 51 chromosomes from E. tencho at meiosis in its hybrids suggests that it may be a diploidized descendant of autotetraploid ancestors with n = 50, which were in turn derived from diploids with n = 25. E. pittieri appears to be an allotetraploid, but its ancestors are not known. The species of Walther's series Spicatae appear to be much less closely related than the similarities in their appearance and habitat suggest.