A New Species of Comolia (Melastomataceae, Marcetieae) from the Sand Dunes of Bahia, Brazil, with Notes on Leaf Anatomy

Abstract

Comolia abaetensis, an endemic new species from the Abaeté and Itapuã sand dunes, Bahia, Brazil, is described and illustrated. Additionally, field images and a geographic distribution map of the new species are provided, together with morphological and leaf anatomy comparisons among the most similar congeners, and a dichotomous key to the species that occur in Brazil. Comolia abaetensis is morphologically similar to C. ovalifolia, but differs from the latter by the following combination of characteristics: glabrous (rarely with sparse trichomes)internodes and hirsute nodes, glabrous leaf blades or rarely with sparse eglandular trichomes, abaxial surface predominantly red with green nuances, glabrous pedicels, cupuliform hypanthium, and filaments of the antesepalous stamens that are 5–6 mm long. Specimens of C. abaetensis have been confused with and/or tentatively determined as C. berberifolia. However, these two species are readily distinguished by the size of the leaves, the length of the trichomes and filaments, and the color of the abaxial foliar surfaces. Comparisons between the leaf anatomy ofC. abaetensis and C. ovalifolia are provided and the occurrence of emergences and hydathodes are here reported for the genus for the first time. Finally, we informally recommend a conservation status of Critically Endangered [CR B1ab (iv) + 2ab (iv)] for C. abaetensis.

New records for different lineages of Melastomataceae in the Brazilian Amazon

“…This species was being approximated to the C. villosa (Aubl.) Triana complex, but after our finding the differences between both are confirmed (see Silva et al 2021a).…”

“…4 mm long; antepetalous stamens 4, with filaments 4-4.5 mm long, appendages ventral 0.3-0.4 mm long, appendages dorsal calcarate, ca. 0.1 mm long, or absent, pedoconnectives 0.2-0.3 mm long, anthers 3-4.5 mm long; ovary ovoid, Notes: Comolia is subordinate to Marcetieae and composed of 12 herbaceous and subshrubby species distributed in Brazil, Colombia, French Guiana, Guyana, Suriname, Trinidad and Tobago, and Venezuela, mainly along coastal sandplain vegetation (restinga), vegetation with predominance of arboreal species on white sand (campinarana) and rocky outcrops Silva et al 2021a). The genus was established by De Candolle (1828) as monotypic, based on the transfer of Rhexia berberifolia Bonpl.…”