Chamaecrista lineata var. jamaicensis

Fruticose erect or in exposed sites diffuse, up to 5-13 dm, the young branchlets and lf-stalks strigulose-pilosulous with straight appressed or narrowly ascending, sometimes mostly incumbent hairs up to 0.2-0.7 mm, the foliage glabrous except sometimes for minutely ciliolate lft-margin and -midrib beneath, the lfts dull or sublustrous olivaceous concolorous; stipules 2.5—5(—6) x 0.6—1.2(—1.4) mm, 5-7- nerved; major lvs up to 3.5-7 cm; petiolar gland 0.35-0.5 mm diam, stoutly stipitate, in profile peg- or pin-shaped 0.7-1.5 mm tall, 0.35-1 mm longer than diam of head; similar but smaller glands often but not always on all or some distal rachis-segments; lfts of major lvs 4-7(-8) pairs, oblong, oblong-oblanceolate or -elliptic, obtuse mucronulate, up to 14-23(-27) x 5-8.5(-9) mm, striate-venulose on both faces, the secondary veins sometimes but not always connected by tertiary venules; pedicels 12-21 mm; sepals up to 7-10 mm; long petals up to 8.511 mm; ovules (7-)8-10; pod 32-42 x 5-6 mm.—Collections: 6.

Open rocky slopes, 100-300 m, very local in two widely separated localities: s.-e. Jamaica (Long Mt. and Cane River gorge, St. Andrew Pa.); Isla de Providencia, Colombia, in the s.-w. Caribbean at 13°21'N, 81°23'W.—Fl. in Jamaica VI-VII, IX-II, on Providencia III-V, but perhaps in both stations irregularly through the year.

The var. jamaicensis seems to have been first mentioned specifically by Bentham (1871, p. 575) as one of three forms of West Indian Cassia polyadena, that form in which glabrous leaves are combined with glands at once "remarkably stipitate and rather numerous"; but the material then available in London (Purdie, March, BM) had already been referred to C. polyadena by Grisebach (1864, p. 210). Britton’s description of Ch. jamaicensis aimed at correcting this error which, nevertheless, was perpetuated by Fawcett & Rendle (1920, p. 113). Bentham (l.c.) had separated his poorly characterized C. polyadena from his C. virgata (=Ch. glandulosa var. swartzii of this account) by the fewer and larger leaflets; and by more numerous ones from C. lineata, supposed to have only 2-4 pairs. Thus it came about that C. jamaicensis long escaped direct comparison with its very close relative C. lineata, now known to vary considerably more than Bentham could forsee in size, number and pubescence of the leaflets. Adams (1972, p. 323 in key, p. 327) maintained C. jamaicensis as specifically distinct from C. lineata because of its glabrous, on average larger leaflets combined with stipitate glands. The pubescence is indeed significant in Jamaica, but not so in Bahaman Ch. lineata, and for leaf-size there is nothing to choose between Harris 12120 from Long Mountain (NY, US = glabrous-leaved jamaicensis with long glands) and Harris 6952 from Malvern in western Jamaica (US = pubescent lineata with sessile gland). The stipitate glands are, in the large view, the only decisive differential character, and ineffective in excluding Ch. jamaicensis from our comprehensive concept of Ch. lineata. Adams (l.c.) suggests that C. jamaicensis may have arisen as a neospecies from a cross between C. lineata and C. glandulosa. One would expect that the progeny of two pubescent parents to be pubescent, which is not the case; and although the largely calcifuge Ch. glandulosa is plentiful about Kingston, we have no evidence that mostly calciphile Ch. lineata is present in southeastern Jamaica. Furthermore the hybrid hypothesis would hardly account for the remotely disjunct population of var. jamaicensis on Providence Island, distant over 700 km off to the southwest of Kingston. We interpret var. jamaicensis as one more product of racial fission at the same level of differentiation as Ch. lineata var. brevipila or var. pinoi.