Eight species of Glandularia are recognized as native to Texas: G. bipinnatifida (having two morphogeographical infraspecific categories, G. b. var. bipinnatifida and G. b. var. ciliata [Benth.] B. L. Turner, comb. nov.); G. canadensis; G. delticola; G. polyantha; G. pulchella (introduced and escaped from cultivation); G. pumila; G. quadrangulata; and G. tumidula. The latest monographer of the genus (R. E. Umber, 1979) recognized 10 species as occurring in Texas. Of these I cannot accept G. wrightii, which is treated as synonymous with G. bipinnatifida var. ciliata, or G. verecunda and G. racemosa, both of the latter treated as synonymous with G. quadrangulata. In addition, Umber's G. bipinnatifida var. brevispicata is treated as synonymous with G. b. var. ciliata. Further, G. quadrangulata, having appendiculate nutlets is also believed to possess forms with exappendiculate nutlets, the latter treated as G. racemosa and/or G. verecunda in his monograph. A key to the Texas taxa is provided, along with partial illustrations, synonymies and distribution maps.

Generic delimitation in the Hymenoxys complex has long been problematic. One taxonomic extreme would recognize only Hymenoxys, whereas the other would split the obviously related taxa into as many as eight genera. This study examined restriction site variation in both cpDNA and nrDNA in the Hymenoxys complex. Fifty-six populations representing 21 species (four with two varieties each) and six of the eight possible genera were analyzed using 21 enzymes, which resulted in the detection of 358 restriction site changes of which 171 were potentially phylogenetically informative. Wagner parsimony using synapomorphic characters generated 26,600 equally parsimonious trees of 223 steps with a consistency index of 0.76 and a retention index of 0.98. Bootstrap analysis indicated that the major clades were strongly supported. The DNA tree supports the recognition of Tetraneuris as a genus separate from Hymenoxys, and the inclusion in Hymenoxys of taxa that at times have been split into the genera Dugaldia, Macdougalia, Phileozera, Picradenia, and Plummera.

Mary S. Young (1872–1919) was one of the first botanists at the University of Texas. Her specimens from different parts of Texas greatly expanded the herbarium collections of the university and her exchanges with other botanists in the United States further increased the herbarium's holdings. Information on her specimens and collection notebooks along with maps as to where she collected are provided.

Ocotea heribertoi is a remarkable new species from very high precipitation rain forests of the Chimalapa-Uxpanapa region of the Isthmus of Tehuantepec in Oaxaca and Veracruz, Mexico. It sports the largest known globose fruit within this large genus, borne in an unusual cupule, while the combination of vegetative and floral features indicate that it is apparently not closely related to any described species.

The genus Pomaria, described by Cavanilles in 1799 but subsequently submerged in either Caesalpinia or Hoffmannseggia, is treated here as a distinct genus and the North American species are revised. This revision provides a key, corrected nomenclature, new combinations, and descriptions for all North American species. One new species is described and distribution maps are provided for each of the nine species.

Fieldwork in connection with the project to document the flora of the Mixteca Alta region of the state of Oaxaca has resulted in the discovery of a new species in the district of Juxtlahuaca, Ageratina juxtlahuacensis. Its distinctive morphological traits are discussed and compared to putative sister species.

A new shrubby species of Pavonia (Malvaceae) from Puebla, Mexico is described and placed in taxonomic context within the genus. Its nearest ally is P. chlorantha from the states of Guerrero and Mexico.

A revision of the Mexican genus Thenardia H.B.K. is presented. Three species are here recognized: T. chiapensis J. K. Williams, T. floribunda H.B.K., and T. galeottiana Baillon. A complete account of synonymy, and typification is provided, as well as a key to species, photographs of types and pollen, and a distribution map of the species.