As determined by extensive molecular studies and critical evaluation of morphology, the genera Eutrema, Neomartinella, Platycraspedum, Taphrospermum, and Thellungiella form a monophyletic assemblage treated here as one genus under the oldest name, Eutrema. The present synopsis of Eutrema includes a listing of all 26 species presently assigned to the genus, including 14 new combinations (E. altaicum, E. botschantzevii, E. fontanum, E. fontanum subsp. microspermum, E. grandiflorum, E. halophilum, E. lowndesii, E. parvulum, E. platypetalum, E. salsugineum, E. verticillatum, E. violifolium, E. wuchengyii, and E. yungshunensis) and 3 new names (E. hookeri, E. schulzii, and E. sherriffii). It also includes a detailed description of the combined genus, distributions, and a key to all species.

Abolboda (Xyridaceae) is a small genus confined to northern South America where it occurs in oligotrophic, wet habitats. Many taxa of Abolboda are endemic and appear to be ecologically specialized. A revised nomenclature is presented that recognizes 23 species and 11 varieties. Abolboda acicularis var. granularis is elevated to the rank of species (as A. granularis).

In a recent morphometric analysis of the Gonolobus complex (subgenus Gonolobus) in the southeastern United States, we found former specific concepts untenable as stated, as the diagnostic characters could not consistently assign individuals to one of two groups. However, our analysis showed a strong geographical component to the distribution of individuals delimited by uniformly and multicolored corollas, which we used as a basis for suggesting that two entities do appear to exist in the Southeast that may deserve recognition at some taxonomic rank. In the present study, we performed analysis of Inter-Simple Sequence Repeats (ISSR) to assess whether the two entities are genetically differentiated and, if so, to what level. We also conducted a cladistic analysis of morphological characters of the subgenus to determine whether the entities emerge as closest relatives. Our ISSR results showed substantial genetic differentiation at 18 loci between the two entities, although no fixed differences between them were detected. At 7 loci, the frequencies of band presence are significantly higher in the multicolored corolla group (MCCG) than in the uniformly colored corolla group (UCCG). At 11 loci they are significantly higher in the UCCG. Nineteen bands are unique to the MCCG, although at various frequencies (3.5–39.0%), whereas only a single band is unique to the UCCG, suggesting that the latter possesses a subset of the MCCG gene pool and is likely a derivative of it. Analysis of 61 parsimony-informative characters using Neighbor-Joining (NJ) and Unweighted Pair-Group Method using Arithmetic means (UPGMA) did not resolve the two groups, consistent with the view of a single species. In a parsimony analysis of morphological characters of 14 species of the subgenus, the two groups consistently appear as closest relatives. This evidence indicates that the complex represents a single evolutionary lineage with two incompletely differentiated morphological subgroups. On the basis of these results, we propose to treat the MCCG and UCCG as two varieties of Gonolobus suberosus. Gonolobus granulatus Scheele is neotypified in association with the required new combination for the UCCG variety. A key to the infraspecific taxa is provided.

The genus Wrightia is revised for the Malesian region. Eight species are recognized, one of which has two subspecies. One new species, Wrightia palawanensis, is described, and one new combination, Wrightia novobritannica, is made. A key to the species is given, and the taxa are described. Lectotypes and neotypes are designated for a number of names.

A new species of the genus Encyclia, endemic to Cuba, is described and illustrated. Encyclia bocourtii is closely related to E. fucata, from which it is distinguished by the size of flower segments, almost double in lenght, and the lateral lobes shorter than the midlobe and not reflexed at apex. The new species also resembles the sympatric E. acutifolia, but it can be distinguished from it by the lateral lobes of the lip, shorter than the mid-lobe, and the non-replicate midlobe.

The Orchidaceae collected by Robert H. Schomburgk in northern South America and the Caribbean are listed in alphabetical order according to their names in current use. Each entry includes bibliography, synonymy, and type information for each name cited. Lectotypes are proposed for the following names: Epidendrum schomburgkii var. confluens, Pseudoeriopsis schomburgkii, Galeandra juncea, Zygopetalum burkei, and Sobralia sessilis. The Orchidaceae in Robert H. Schomburgk's “Drawings of Guiana Plants” at the Botany Library, The Natural History Museum are presented in an appendix.