Chamaecrista deeringiana Small & Pennell

Authors

Howard S. Irwin, Rupert C. Barneby

Authority

Irwin, Howard S. & Barneby, Rupert C. 1982. The American Cassiinae. A synoptical revision of Leguminosae tribe Cassieae subtrib Cassiinae in the New World. Mem. New York Bot. Gard. 35, part 2: 455-918.

Family

Caesalpiniaceae

Scientific Name

Chamaecrista deeringiana Small & Pennell

Type

". . . near Silver Palm, Dade County, Florida, collected in flower and fruit June 22, 1915, J. K. Small, C. A. Mosier & G. K. Small 6454..."—Holotypus, NY!—Cassia deeringiana (Small & Pennell) Macbride, Contrib. Gray Herb., n. ser. 59: 24. 1919.

Synonyms

Cassia deeringiana (Small & Pennell) J.F.Macbr., Chamaecrista deeringiana Small & Pennell, Cassia deeringiana (Small & Pennell) J.F.Macbr.

Description

Species Description - Perennial herbs with simple or sparingly branched stems erect or ascending, solitary or few together, from knots or short vertical caudices arising from shallowly buried, horizontally running woody rhizomelike roots, at anthesis 3-9 dm, except for the subterranean organs and perennial life-span closely resembling sympatric forms of Ch. fasciculata, appearing glabrous, but lf-stalks at least thinly and often also the stems distally, pedicels and ovary minutely appressed- or incurved-puberulent, the lfts glabrous, prominently venulose. Stipules (ovate-) lance-acuminate (2.5-)4-10.5 x 0.8-1.9 mm, from oblique or shallowly subcordate base prominently 7-13-nerved, glabrous, persistent. Adult lvs 3-8.5 cm; petiole with pulvinus 3-7(-9) mm; gland 1, near middle of petiole proper, round or elliptic, shallowly concave or discoid (0.5-)0.6-1.6(-2) mm diam, sessile or stoutly short-stipitate, in profile 0.25-1 mm tall, 0.25-1 mm shorter than diam of head; lfts of adult lvs up to 8-18(-20) pairs, narrowly lance- or linear-oblong, obtuse mucronulate or subacute, up to 9-17(-20) x 2-3.3(-"3.7") mm, from base 5-7-nerved by the centric or slightly displaced midrib with on its broad side 3-5, on its narrow one usually 1 shortly incurved-ascending primary veins, the midrib thence penninerved with (3—)4—6(—7) major and as many weaker or almost as strong intercalary secondaries, the venulation usually sharply prominulous on both faces. Inflorescence and fl as in Ch. fasciculata, but the petals reportedly (Isely, 1975, p. 79) richer yellow, all or only 2-3 red-blotched at the claw, the long abaxial petal (12-) 14-19 x 7-16 mm; androecium 10-merous, the longer 2-3 of the yellow, dull reddish or particolored anthers 8—10.5 mm; style linear 6—8 mm, ovules 12-19. Pod 35-70(-85) x 4.5-6 ("-7.4" fide Pullen) mm; seeds little known, apparently not different from those of Ch. fasciculata.—Collections: 11.

Distribution and Ecology - Thin pine and pine-oak woodlands below 200 m, in deep sands or thin sandy humus overlying coral limestone, locally abundant but of discontinuous range in Florida and adjoining states: centr. and (more plentifully) s. peninsular Florida, from Hernando County s. to Key Largo; w. Florida, from the Apalachicola w. to the Escambia River, there extending n. just into Alabama; and apparently disiunct on the upper Flint River in w.-centr. Georgia (Taylor and Peach counties).- Fl. Ill-VII and in s. Florida sporadically through the fall and winter.

Discussion

A species of enigmatic origin and oddly discontinuous dispersal, recognized by all modern students of the group as closely akin to Ch. fasciculata, from glabrescent sympatric forms of which it differs only in the cordlike horizontal perennial root, a structure duplicated nowhere in sect. Chamaecrista. Isely (1975, l.c.) finds unbranched stems and red anthers helpful in identifying specimens of Cassia deeringiana severed from their characteristic understructure, but these features are fallible, the more vigorous stems being by no means always simple, and the anthers, as noted by Small (1919, l.c.) varying from red to yellow. Pullen (1963, l.c.) raises the question as to whether C. deeringiana, in virtue of its perennial life-span and interrupted dispersal, may not represent a relict stock ancestral to Ch. fasciculata and perhaps other annual kindred. We have no empirical data with which to oppose this hypothesis, but think it a weak one if examined in the context of sect. Chamaecrista as a whole. The horizontal root- system, which appears to fulfill in the shallow soils of fire-prone pine savannas of Florida the function of a xylopodium in the campo cerrado of eastern Brazil, is (unlike a vertical taproot) a highly specialized one, and moreover coincides, in Ch. deeringiana, with the also specialized supra-axillary inflorescence of the "mimosoid" chamaecristas. We think it unlikely that a pseudo-rhizomatous ancestor of an enormous, highly diversified group of species dispersed throughout the tropics of the world should survive only in a small extratropical enclave in southeastern United States, the more so when it is known to resemble most closely the one member of that group which is itself entirely extratropical. We would suggest, to the contrary, that Ch. deeringiana arose in situ from sympatric Ch. fasciculata, of which it preserves intact every gross morphological feature above the root; and, further, that it is possibly biphyletic, a circumstance that would explain its bicentric range and curious absence from northern peninsular Florida (cf. Isely, 1975, map 26, where incidentally the Georgia stations are overlooked).

Distribution

Florida United States of America North America| Alabama United States of America North America| Georgia United States of America North America| United States of America North America|