Chamaecrista portoricensis (Urb.) O. F. Cook & G. N. Collins

• Title

  Chamaecrista portoricensis (Urb.) O. F. Cook & G. N. Collins

• Authors

  Nathaniel Lord Britton, Frances W. Horne

• Scientific Name

  Chamaecrista portoricensis (Urb.) O.F.Cook & G.N.Collins

• Description

  Flora Borinqueña Chamaecrista portoricensis Retama Family Caesalpiniaceae Senna Family Cassia portoricensis Urban, Symbolae Antillanae 1; 317. 1899. Chamaecrista portoricensis Cook & Collins, Contributions from the United States National Herbarium 8: 113. 1903. This plant is endemic in Porto Rico, and restricted in distribution to hillsides in the western and southwestern districts at lower and middle elevations, often growing in soil underlain by, and derived from the disintegration of serpentine rocks, but sometimes in limestone areas. Serpentine rocks underlie large areas of western Porto Rico, and yield characteristic soils in decaying; some study has been made of their vegetation, and some species of plants appear to be restricted to these areas, but further field study is necessary to accurately determine this interesting question. We give an account of the genus Chamaecrista with our description of Chamaecrista Swartzii; in the Porto Rico Flora we have 10 species in all, and 4 of them have been selected for illustration in this work. Chamaecrista portoricensis is a branched shrub, occasionally about a meter in height, usually much lower, with finely hairy branches. The leaf-stalks are short, and bear a round, depressed gland; the lance-shaped stipules are long-pointed, from 3 to 8 millimeters long; the leaves have from 3 to 11 pairs of smooth, mostly oblong leaflets, 6 to 15 millimeters long, shining, strongly veined, blunt or pointed, with callous margins, the flower-stalks are shorter than the leaves, and bear a single flower, or sometimes 2; the lance-shaped, long-pointed sepals are thin and from 6 to 8 millimeters long; the broad petals are from 10 to 15 millimeters long. The short-hairy pods are about 6 centimeters long, or less and from 4 to 6 millimeters wide. A closely related species, Chamaecrista granulata, inhabits sand-dunes and coastal thickets in the dry, southwestern districts, and the small islands Mona and Cayo Muertos; it differs from the one here illustrated in having granular-puberulent leaflets without callous-thickened margins and the gland on the leaf-stalk is stalked.