Chamaecrista calycioides (Collad.) Greene var. calycioides

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 calycioides (Collad.) Greene var. calycioides

Type

Cassia calycioides DeCandolle ex Colladon, 1816, l.c., sens. str.—"Hab. in Cayenna."—Holotypus, without further data, collector not recorded (but perhaps J. B. Patris), G-DC! = F Neg. 7003.

Synonyms

Cassia calycioides DC. ex Collad., Chamaecrista aristellata Pennell, Cassia aristellata (Pennell) Cory & H.B.Parks, Cassia pedersenii Burkart, Chamaecrista aristellata Pennell

Description

Species Description - Habit and vesture of the species; lvs 1.5-6 cm; gland(s) 0.2-0.9 mm diam, 0.3-1.3 mm tall, the stipe usually filiform, sometimes stout; lfts of adult lvs 5-12 pairs; peduncles 0-3.5 mm, l(-3)-fld; fruiting pedicels 2-12(-25) mm: sepals 5-12.5 mm; petals 5-14 mm, varying from ±1 mm shorter to 3 mm longer than sepals thecucullus strongly differentiated, commonly ± twice as wide as the rest; style 1-5 mm, either filiform or (especially when short) a little dilated and at stigma up to 0.3-0.4 mm diam; stamens 8-10, the long anthers 3.3—6(—7.2) mm; pod as described in key, the valves usually pilose, sometimes merely puberulent, exceptionally glabrate.—Collections: 57.

Distribution and Ecology - Savanna, campo, pampa, usually in sandy soils, below 600 m, widely scattered through the tropics and subtropics of the Americas, apparently nowhere common; Coastal Plain of s. Texas (Turner, l.c. sub C. aristellata, map 35; Isely, l.c., map 21) and adjacent Tamaulipas; Isthmus of Tehuantepec, Oaxaca, Mexico; n. Venezuela (Carabobo and Cojedes to Monagas, mostly on the Orinoco slope of the coastal cordillera); foothills of Sa. Pacaraima in Terr. Roraima (Sas. do Mel and de Xiriri), Brazil and probably adjacent Guyana; French Guiana; scattered over n.-e. and e. Brazil from the lower Amazon valley in Pará to Rio Grande do Norte and e.-centr. Goiás; and again occasional in widely scattered stations within the lower Paraná-Paraguay basin from n.-centr. Paraguay (Río Apa) to s. Brazil (n.- centr. São Paulo) and n. Argentina (Santiago del Estero and Corrientes).—Fl. in Texas and Mexico V-X, in Venezuela III-VIII, in Brazil nearly throughout the year, in far south X-III.

Discussion

The immense distances intervening between major populational centers and remotely scattered smaller ones of var. calycioides, such as savanna-enclaves on the lower Amazon, are such as must divide the whole gene pool into decisively isolated segments and therefore favor or even promote morphological differentiation. In the circumstances, however, it is the essential homogeneity, not the internal diversity of the species that is more remarkable. Apart from composition and density of the duplex vesture, unstable everywhere in Chamaecrista, the variable phenetic characters are: number of leaflets; diameter and height of petiolar glands; length of perianth; and length of style. In Texas and adjoining Mexico the leaflets of adult leaves are mostly 7-9 pairs, the gland very small (0.2-0.4 mm diam) and elevated on a filiform stalk, while sepals and petals are relatively short (±5.5-7 mm) and the stout style only 1.1-2 mm long. The typus of C. calycioides from Cayenne and all the samples known from Brazil between Pará and Rio Grande do Norte are essentially like the Texan plant except that the leaflets are slightly more numerous, up to 9—12(—13) pairs in adult leaves. In Venezuela and Oaxaca we find the same gland and leaflets as the last combined with a larger flower, the sepals up to 8-11 mm, the petals to 8.5-14 mm, and a linear style 2.5-4.5 mm long. The southern foothills of Pacaraima harbor a form of var. calycioides, perhaps taller and more erect than others, in which the flower and leaflets of the last are combined with a coarse gland 0.5-0.9 mm diameter elevated on a stout stipe no longer than the diameter of the head. In the Paraná- Paraguay basin the leaflets are once again relatively few as in Texas, mostly 5-9 pairs, but with this type of leaf the flower varies greatly in amplitude and the style from 1 to 5 mm in length. Here the gland, while small-headed, tends to be shorter-stalked than northward. In the context of compatriot forms such as represented by T. Meyer 6074 (A) from Ituzaingó, Corrientes, the typus of C. pedersenii is unique in one feature only, the pedicels, elsewhere never above 12 mm long, being greatly elongated, up to 2.5 cm, carrying the flower well beyond the tip of the short subtending leaf. Despite its visually striking nature we are obliged to reduce C. pedersenii to the status of a taxonomically negligible minor variant Our one collection of var. calycioides from Santiago del Estero, with the foliage and gland of C. pedersenii but the small, short-pedicelled flower prevalent in eastern Brazil or Texas, is scarcely less well-marked.

Distribution

Texas United States of America North America| Tamaulipas Mexico North America| Oaxaca Mexico North America| Mexico North America| Venezuela South America| Carabobo Venezuela South America| Cojedes Venezuela South America| Monagas Venezuela South America| Roraima Brazil South America| Guyana South America| French Guiana South America| Pará Brazil South America| Goiás Brazil South America| Paraná Brazil South America| Paraguay South America| São Paulo Brazil South America| Argentina South America|