A new species of morning glory from southwestern Mexico, Ipomoea cuprinacoma (Convolvulaceae), is described. The species is assigned to Ipomoea series Arborescentes with other stout lianas and trees, and distinguished from I. populina on the basis of slender stems, canescent peduncles and leaf blades, exclusively axial inflorescences, and long, pale-coppery seed hairs.

Amaranthus torreyi and A. fimbriatus are partially sympatric, seemingly weedy species native to the southwestern United States and northwestern Mexico. A taxonomic account of each is provided, along with maps showing their distribution. Lectotypification of A. venulosus is provided; the taxon is treated as a form of A. fimbriatus.

A revision of Phyllanthus sect. Hylaeanthus (subg. Conami) treats seven species, mostly with a primarily Amazonian distribution, as well as one species of uncertain affinity. The section is characterized within subgenus Conami by a tendency to dioecy, unramified branchlets, distinctive pollen grains with pilate exine ornamentation, and indehiscent fruits with sarcotestal seeds. Two species are described as new: Phyllanthus puntii from western Brazil (Acre) and Bolivia, and P. awaensis from northern Ecuador. Two new subspecies of Phyllanthus attenuatus are described: P. a. ssp. incarum from western Amazonia in Ecuador, Peru, and Colombia; and P. a. ssp. tucuruiensis from Amazonian Brazil. Phyllanthus manausensis is reduced to a synonym of P. madeirensis. A key is provided to help distinguish specimens of taxa in sect. Hylaeanthus from superficially similar but unrelated species of other subgenera of Phyllanthus.

Stenanona flagelliflora is described as a new species of small, flagelliflorous tree from deep-soil hill rain forests of the Uxpanapa-Chimalapa region of the Isthmus of Tehuantepec, in Veracruz and Oaxaca, Mexico. In flagelliflory, flowers are borne on essentially leafless modified whip-like branches that trail across the ground; this is the first report of the phenonenon for the flora of Mexico or Central America. The phenomenon of flagelliflory and its worldwide occurrence are reviewed. The Central American genus Stenanona is not closely related to other New World annonaceous genera with flagelliflorous species but rather is likely most closely related to the Old World species of Polyalthia with superficially inaperturate but internally disulculate pollen. The distribution of S. flagelliflora and of its closest relatives, as well as the existence of flagelliflory in Mexican rain forest, provide additional data supporting the persistence of rain forest lineages in Mexico throughout climatically adverse periods of the late Cenozoic. The new species is considered to be Critically Endangered (CR) under the IUCN Red List classification.

A new infraspecific taxon of the widespread western species Stanleya pinnata is described from the Big Bend Region of Trans-Pecos, Texas as var. texana. The taxon is distinguished from other varieties of S. pinnata in having smaller flowers, nearly glabrous gynophores, and lanceolate entire leaves which are, so far as known, never deeply divided or pinnate. It is isolated from the closest known populations of S. pinnata by some 500 km and is represented by small populations largely restricted to bare gypso-calcareous outcrops in southern Brewster Co., Texas. In addition, the long recognized S. pinnata var. integrifolia is reduced to the rank of forma integrifolia.

The taxonomic history, defining characters, and relationships of the genus Mortoniodendron are briefly sketched. Characters that define M. pentagonum, a species known from a limited area in Guatemala, are elaborated. A closely related but distinct species from Veracruz, Mexico, M. uxpanapense Dorr & T. Wendt, is described and illustrated. The new species is considered to be Critically Endangered (CR) under the IUCN red list classification.

Herbarium and field studies of the chiefly neotropical genus Capraria have led to the recognition of four species. Capraria frutescens and C. mexicana are essentially endemic to Mexico. Capraria biflora is a widespread species that occurs throughout Mexico, Central and South America, the West Indies, and southern Florida. Capraria peruviana grows in northwestern South America and the Galápagos Islands. A complete account of synonymy and typification is provided, along with a key to species, scanning electron micrographs of pollen, stigmas and seeds, photographs, illustrations, and distribution maps.