Chamaecrista glandulosa var. swartzii (Wikström) H.S.Irwin & Barneby

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 glandulosa var. swartzii (Wikström) H.S.Irwin & Barneby

Type

Cassia glandulosa var. swartzii (Wikstrom) Macbride, Contrib. Gray Herb., n. ser. 59: 26. 1919, based on C. swartzii Wikstrom, Vetensk. Acad. Handl. 1825: 430. 1826.—"Hab. in Isula S:ti Bartholomaei: Forsström."—Holotypus, labelled by Swartz "Cassia n. sp

Synonyms

Cassia glandulosa var. swartzii (Wikstr.) J.F.Macbr., Cassia swartzii Wikstr., Chamaecrista swartzii (Wikstr.) Britton, Cassia otterbeinii G.Mey., Cassia polyadena DC., Chamaecrista polyadena (DC.) Britton, Cassia parkeriana DC., Cassia chamaecrista var. glandulosa Kuntze, Chamaecrista complexa Pollard, Chamaecrista polyadena (DC.) Britton

Description

Species Description - When adult suffruticose, fruticose, exceptionally subarborescent, at anthesis (1.5-)3-24(-40) dm, erect in sheltered sites, diffuse or prostrate in exposed ones, the stems and lf-stalks puberulent with incurved or some spreading whitish hairs to 0.2-0.8 mm, the lfts glabrous above, often so beneath, concolorous or paler beneath and then often red-margined when fresh. Stipules triangular to lance-acuminate, 1.5-8(—11) x 0.4-1.7 mm. Major cauline lvs 3-12 cm, in depauperate states only 2-3 cm, the petiole 2.5-6(-7) mm; petiolar gland 1(—3), urceolate or discoid, 0.15-0.9 mm diam, stipitate but sometimes shortly so, in profile 0.2-1.1(-1.5) mm tall, (0.3-)0.1 mm shorter to 0.8(-0.95) mm longer than diam of head; lfts of larger lvs (5-)8-23 pairs, linear-oblong to oblong-obovate, the largest (6-)7-25 x (1.2-)1.5-6.5(-9.5) mm, the secondary pinnate venulation of (5—)6—12 pairs of major secondaries with or without solitary or paired intercalary minor ones. Pedicels at anthesis (6-)7-28 mm, in fruit (7-)8-28 mm; sepals up to (7-)8-13.5 mm; long abaxial petal (9-) 10-18 x (6—)8—17.5(—21) mm; style (3-)3.4—4.2 mm; ovules (8—)9—11. Pod (22-)27-52(-60) x (3-)3.5-5.5 mm, thinly puberulent.—Collections: 160.—Fig. 37 (androecium).

Distribution and Ecology - Open grassy banks, thickets, forest margins, dunes, sometimes on coral limestone and colonizing recent lava-flows, becoming dwarfed and prostrate on cliffs, shores, and windy summits, 1-600 m, widespread and locally abundant throughout the chain of islands forming the e. and n.-e. periphery of the Caribbean: Puerto Rico (with islas Vieques and Culebras); Virgin Is. (St. Thomas, St. Jan, Tortola Virgin Gorda, Anegada, St. Croix); Leeward Is. (Anguilla, Saba, St. Eustatius St Kitts, Barbuda, Antigua, Monserrat, Guadeloupe, Marie Galante), Windward Is (Dominica, Martinique, St. Lucia, St. Vincent, the Grenadines, Grenada)- Barbados. Reported from Cuba, Hispaniola and Trinidad, but apparently by error —Fl. most profuse X-V, but sporadically throughout the year.

Discussion

The var. swartzii, as defined herein the most widespread Antillean form of Ch. glandulosa, is highly adaptable ecologically and phenologically plastic, subject to two, sometimes parallel modalities of variation, one adaptive, the other seasonal. A multitude of minor races, each embodying its own range of minor variations, and different one from the next in stature, in amplitude, coloration and venation of foliage, in size and number of petiolar glands, and in size of flower, occupy a great range of natural and disturbed habitats, from dunes and coral reefs within reach of salt spray up into the edges of mesic woodland or rain-forest, and thence out into hedges, pastures, and fallow ground. In protected sites the plants, even though apt to flower precociously as simple herbs, when adult become erect, branching shrubs up to two or rarely four meters tall, with relatively long primary leaves and many leaflets, superficially very different from the diffuse or prostrate, small-leaved and generally thrifty life-form imposed by exposure to wind or by barren soils. But where the seasons are well marked, the amply leafy plant, of whatever stature, discards its larger leaves during periods of water scarcity, nevertheless often continuing to flower from axillary brachyblasts clothed in the short, simple foliage that from the first and permanently characterizes the xeromorphic ecotypes.

While much of the polymorphism noted in var. swartzii can be accounted for in these terms, some must be attributed to the sort of genetic diversity that arises naturally under conditions of insular dispersal. The diameter and number of petiolar glands and the development of their stipes appear rather stable within a given population and sometimes within the confines of some smaller islands, as does the outline of the leaflets, regardless of their size. While the total dispersal of gland-types appears to be random and capricious, it is otherwise with the foliage. From Puerto Rico eastward through the Virgin Islands (except St. Croix) and smaller northern Leewards the average leaflet of a plant’s most ample leaf is relatively narrow (±1.5-3 mm) and concolorous; on St. Croix and the length of the Windward chain to Grenada and Barbados the comparable leaflet is commonly broad (±3-6.5 mm) and paler beneath than above. These wider and often at the same time longer leaflets tend to have more elaborate and more sharply raised secondary (pinnate) venulation, with at least one and sometimes two distinct intercalary venules between each successive major one. Correlation between glands, leaflets, and venulation is not strong enough, however, to sustain any credible infraspecific taxa.

The typus of Cassia polyadena, a species maintained (under Chamaecrista) by Britton & Rose (1930) even though Britton had earlier (1917, p. 10) expressed lack of confidence in its distinctness from Ch. swartzii, represents a form with few (±14), broad, bicolored leaflets combined with several small, short-stalked rachis-glands, matched by collections from several of the Windward Islands and from Barbados. However, sympatric plants with the same leaf-type may have long-stipitate glands, either solitary on the petiole or also along the rachis, and the small glands of C. polyadena are encountered on Puerto Rico in conjunction with narrow leaflets. The typus of Ch. complexa was early recognized as being exactly Wikstrom’s C. swartzii. Those of Cassia parkeriana and C. otterbeinii, referred by Bentham (1871) to C. riparia and C. glandulosa respectively, are typical narrow-leaflet var. swartzii, the first certainly and the second most probably only cultivated in Guyana, where Parker recorded the vernacular name Franchepan. The ten supposedly sterile but unequal and apically notched filaments described by Meyer in the protologue of C. otterbeinii are, of course, not filaments but the elongate anther-sacs characteristic of Chamaecrista.

The range of var. swartzii may possibly extend to Trinidad, but we have seen no complete specimen from that island. Fragments of Hunt 1891 (=Trinidad Herb. 5864 at NY are labelled Chamaecrista swartzii in Britton's hand, but are too fragmentary for confirming identification

Distribution

Puerto Rico South America| Vieques Puerto Rico South America| Virgin Islands South America| Saint Thomas Virgin Islands of the United States South America| St. Jan Virgin Islands South America| Tortola Virgin Islands South America| Anegada Virgin Islands South America| Saint Croix Virgin Islands of the United States South America| Anguilla South America| Saba South America| Sint Eustatius South America| Saint Kitts and Nevis South America| Antigua and Barbuda South America| Antigua and Barbuda South America| Guadeloupe South America| Pointe-à-Pitre Guadeloupe South America| Dominica South America| Martinique South America| Saint Lucia South America| Saint Vincent and the Grenadines South America| Grenada South America| Barbados South America| Cuba South America| West Indies| Trinidad and Tobago South America|