Chamaecrista caribaea

Title

Chamaecrista caribaea

Authors

Howard S. Irwin, Rupert C. Barneby

Scientific Name

Chamaecrista caribaea (Northr.) Britton

Description

10. Chamaecrista caribaea (Northrop) Britton, Bull. Torr. Club 44: 8. 1917. Cassia caribaea Northrop, Mem. Torr. Club 12: 39. 1902.—Typus infra sub var. caribaea indicatur.

Erect shrubs of ultimately bushy, round- or flat-topped outline, when crowded few-stemmed and spindly, at anthesis 4-15 dm, with slender pallid or fuscous furrowed trunks stiffly branched distally, the annotinous branchlets and lf-stalks minutely strigulose with appressed or subappressed straight or incurved hairs up to 0.1—0.4 mm and sometimes in addition pilosulous with spreading ones up to 0.5—1(—1.4) mm, exceptionally glabrate, the pedicels sometimes thinly pilose, the stiffly chartaceous lustrous concolorous olivaceous lfts brunnescent on drying, glabrous or minutely ciliolate at base.

Stipules erect appressed, subsymmetrically triangular-subulate or lance-attenuate (1—) 1.5—6.5 x 0.4—1.2 mm, from base (3—)4—8-nerved, in age often nigrescent, persistent.

Major lvs up to 1.7—8 cm, petioled or subsessile; pulvinus swollen, wrinkled when dry, 0.6-4 mm; petiole proper 0.4-9 mm, at middle 0.5-0.9 mm diam, narrowly shallow-sulcate ventrally; petiolar gland 0—1, when present usually much above middle of petiole proper, discoid or cupulate, stipitate but sometimes only shortly so, in profile commonly tack- or broadly trumpet-shaped, sometimes squatly drum-shaped or obconic, (0.4-)0.6-1.5 x (0.4-)0.45-1.4(-1.5) mm, in profile (0.7-)0.4 mm shorter up to 0.9 mm longer than diam of head; similar but smaller glands below each or below the last pair of lfts; lfts of major lvs 2-10 pairs, elliptic, oblong-, oblance-, lance- or obovate-elliptic, obtuse-acuminulate, acute, obtuse, or sometimes obovate-emarginate, all mucronulate, up to (12-) 13-31 x 4-19 mm, at base broadly rounded to cordate on proximal and cuneate to subcordate on distal side, from base 4-9-nerved by the subcentric midrib with on the proximal side 2-6, on the distal side 0-3 short incurved-ascending primary veins, the midrib thence penninerved with 4-8 major secondary veins with or without 1-3 intercalaries, these faint or sometimes almost as strong as the major ones, the lft-blade then multistriate, the venulation above immersed or bluntly prominulous, beneath either faintly or sharply prominulous.

Peduncles exactly axillary 0-5 mm, 1-2-fld; pedicels 15-55 mm, bracteolate 2.5-20 mm below calyx; buds ovoid-acuminate glabrous or thinly pilosulous; sepals ovate-acuminate up to 8.5-11 mm; petals yellow heteromorphic, 2-3 smaller obovate- or oblong-obovate-cuneate, 1-2 larger obovate- to flabellate-cuneate, 1 of these abaxial up to (12.5-) 13-16 mm, the oblique cucullus a little shorter; androecium 10-merous, the anthers yellow or reddish, the 2-3 longest up to 5.5-7.3 mm, ovary strigulose, sometimes thinly so; style linear 4.5-6 mm, incurved distally; ovules 8-13.

Pod linear-oblong or linear 36-60 x 5-6.5 mm, the ripe valves atrocastaneous, dark purplish, or pinkish-brown, thinly or remotely strigulose, or glabrate except along the sutures; seeds 3.2-5.3 mm, the testa dull brown, faintly pitted, reticulately crackled.

A truly shrubby chamaecrista, notable for its glossy glabrous foliage and relatively large flowers, Ch. caribaea is everywhere sympatric with some form of the polymorphic Ch. lineata var. lineata, which differs in its dull, usually glaucescent and commonly at least dorsally pubescent leaflets combined with sessile petiolar glands and at least shortly adnate, supra-axillary peduncles. Our concept of Ch. caribaea readily accommodates four Brittonian chamaecristas but these admittedly are not identical, and we have been able to sort the material into three geographic categories: a well differentiated var. caribaea, with subsessile leaves lacking a petiolar gland and 2-4 pairs of relatively small, simply venulose leaflets, endemic to the central Bahamas; and the very closely related vars. lucayana and inaguensis, collectively different from var. caribaea in the well-developed glan- duliferous petiole and larger, more elaborately venulose leaflets, distinct from each other in leaflet-number and a geographic gap in the Bahamas corresponding with the latitudinal interval 22-23°N. A similar taxonomic solution was independently worked out by Gillis (Phytologia 35(2): 90-91. 1976), who, however, did not recognize named varieties of C. caribaea sens. lat.