TYPE: BRASIL. Goia's: Chapada dos Veadeiros, Mun. de Alto Paraiso, a 9 km da ciudade, rod. GO 1 18 para Teresina de Goias, 14º03'02"S, 47º31'26"W, 1520 m, 28 Jul 1994, Aparecida da Silva, Filgueiras, Resende, Gon,calves, Santos, Silva, Felfili, Nogueira Silva & Aure'lio Silva 2117 (HO- LOTYPE: IBGE; ISOTYPE: US).
This new species was discovered during the data collection phase of the project Biogeografia do Bioma Cerrado which was a collaborative project of the Instituto Brasileiro de Geografia e Estatistica (IBGE), Universidade de Brasilia (UnB), and Empresa Brasileira de Pesquisa Agropecuaria (EMBRAPA) (Felfili et al., 1994). The location was one of the study sites of the project which was visited several times because of its floristic richness. The senior collector, Maria Aparecida da Silva, made a special effort to collect the inconspicuous forbs below the grass layer. On their first visit to the site, she examined the ground below the grasses, and Borreria dimorpha was not there. During their second visit, she found it below the grass layer in the same area that she had examined previously. Without her careful examination below the grasses, it would have been overlooked. On their third visit to the site, she could find no trace of B. dimorpha in the same area. The species is obviously an annual.
Borreria dimorpha has two distinct vegetative morphotypes on each individual. At first it is a rosette plant of very low stature with its narrowly ovate leaves condensed and close to the surface of the ground. After forming 3-5 nodes, its morphology shifts from rosette to a tall, slender herb. The upper internodes and leaves are elongate, and the leaf-blade is linear. The specific epithet dimorpha refers to this vegetative habit.
At first glance, the tall, slender phase of B. dimorpha resembles Borreria tenuis DC., B. gracillima DC., and B. tenera DC. of sect. Borreria ser. Tenellae K. Schum., but its stigmatic morphology excludes it from ser. Tenellae. The stigma has two long branches about equal in length to the style (Fig. 9E), which places it in sect. Borreria ser. Latifoliae K. Schum. In ser. Latifoliae, B. dimorpha resembles B. pygmaea Spruce ex K. Schum. var. pygmaea from Venezuela, but differs by the characters set forth in the above diagnosis.