Chamaecrista nictitans

  • Title

    Chamaecrista nictitans

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Chamaecrista nictitans (L.) Moench

  • Description

    51. Chamaecrista nictitans (Linnaeus) Moench, Meth. pi. hort. bot. Marburg. 272. 1794, quoad descr., exclus. syn., hic magnopere ampliata.—Cassia nictitans Linnaeus, Sp. Pl. 380. 1753.—Typus infra sub var. nictitanti indicatur.

    Monocarpic (under special circumstances over-wintering and weakly lignescent basallv but never durably perennial or fruticose); peduncles adnate to stem, the pedicels appearing supra-axillary; all other phenetic characters labile and subject to wide ranges of variation.

    We have brought together here into one multiracial Ch. nictitans all but one of the American monocarpic Chamaecristae Mimosoideae which, as inferentially predicted by Bentham a century ago, are found to form a continuous fabric of variation that yields only very reluctantly to taxonomic analysis. Allowance being made for conspicuous individual variation in habit, vesture, glands, and flower- size, the constituent races of Ch. nictitans share with Ch. glandulosa sens. lat. and Ch. fasciculata a monotonous sort of common facies which points, in our judgment, to a very close relationship among all and a presumably recent, doubtless continuing differentiation from common antecedents. The species is here arbitrarily separated off from Ch. glandulosa by monocarpic duration, which may well have arisen independently from several fruticose immediate ancestors, so that we cannot be sure that Ch. nictitans is a phyletically pure assembly. The one other American monocarpic ally already mentioned as excluded from our comprehensive concept of Ch. nictitans is, of course, Ch. fasciculata itself. While this can be distinguished by multiple characters from similar, distantly allopatric, large-flowered, longistylous Ch. nictitans subsp. disadena and subsp. brachypoda, it is no longer separable from the whole of Ch. nictitans by any single morphological difference. However, since Ch. fasciculata is endemic to the United States and sympatric only with small-flowered brachystylous elements of subsp. nictitans, the objections to its exclusion will be more theoretical than practical.