Chamaecrista mirabilis Pollard

• Title

  Chamaecrista mirabilis Pollard

• Authors

  Nathaniel Lord Britton, Frances W. Horne

• Scientific Name

  Chamaecrista mirabilis Pollard

• Description

  Flora Borinqueña Chamaecrista mirabilis Tamarindillo borinqueño Porto Rico Partridge Pea Family Caesalpiniaceae Senna Family Chamaecrista mirabilis Pollard, proceedings of the Biological Society of Washington 15: 19. 1902. Cassia mirabilis Urban, Symbolae Antillanae 4: 276. 1905. The soil of large areas of the northern coastal plain of Porto Rico is a fine, white, silicious sand, in which grow a considerable number of kinds of plants not occurring elsewhere on this island, a few of them endemic species, not to be found elsewhere; the plant here illustrated is one of these, locally abundant and forming large patches. Geological and soil studies have shown that these white sands are the nearly insoluble residue from the atmospheric erosion of nearly horizontally stratified Tertiary rocks, mostly limestones. Stages of this erosion are apparent in the numerous picturesque "mogotes" or "haystack hills", more or less isolated remnants of a former, thick layer of limestone which overspread the region at least as far east as Loiza or farther; sand may indeed be seen in the rock exposed in some of these hills. The proximity of some of the accumulations of this sand to limestone hills has sometimes led to the conclusion that it is calcareous, but where ever tested, no chemical reaction for lime has been obtained. An account of the genus Chamaecrista is given with our description of Chamaecrista Swartzii. The name Partridge Pea is used for northern relatives of these plants. Chamaecrista mirabilis (admirable) is a small, nearly prostrate shrub, with slender stems about 0.6 meter long, or shorter, the branches sometimes ascending, or erect,finely hairy when young; it often forms patches several meters across, almost to the exclusion of other vegetation. The once-compound leaves are short-stalked, their stalks bearing from 1 to 3, small, round, stalked glands; there are from 3 to 17 pairs of narrow, smooth, thin, pointed leaflets 4 to 6 millimeters long; the attractive, yellow flowers are usually solitary at the leaf-axils, borne on very slender stalks; the 5 sepals are from 6 to 9 millimeters long; the 5 petals are from 10 to 15 millimeters long, one of them much broader than the others. The pod is from 2 to 2.5 centimeters long, 2 to 2.5 millimeters wide, sparingly hairy, abruptly short-tipped. Our illustration was first used in "Addisonia", plate 335, June, 1925.