Senna corifolia (Benth.) H.S.Irwin & Barneby
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Authors
Howard S. Irwin, Rupert C. Barneby
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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 1: 1-454.
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Family
Caesalpiniaceae
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Scientific Name
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Type
Typus infra sub var. corifolia indicatur.
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Synonyms
Cassia corifolia Benth.
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Description
Species Description - Shrubs, sometimes arborescent in age, at anthesis 1-3 m, the trunks reaching 6 cm diam, the annotinous branchlets and lf-stalks livid-castaneous smooth, either glabrous throughout, or the young stems, lf-stalks and rarely the dorsal face of lfts pilosulous with ascending pale or rufescent hairs up to 0.2-0.4(-0.5) mm, the ample stiffly chartaceous foliage and foliaceous stipules all olivaceous sublustrous above, paler dull or sometimes subglaucescent beneath, intricately reticulate on both faces, the inflorescence an open pyramidal panicle of racemes well exserted from foliage. Stipules foliaceous amplexicaul persistent, transversely reniform (0.7-)1-3 x (1.5-)2-5.5 cm, broadly rounded at both ends, palmately many-nerved from base, thence intricately reticulate like lfts. Lvs (disregarding depauperate ones subtending lower racemes) 1-2 dm; petiole including livid wrinkled pulvinus 1.5-3.5(-4) cm, at middle subterete 1.2-2.2 mm diam, distally like rachis openly sulcate ventrally; rachis 2-9.5 cm; glands between all pairs of lfts sessile or almost so, plumply ovoid, ovoid-ellipsoid or subglobose, acute or obtuse, 0.9-1.6 x 0.6-1.4 mm; pulvinules wrinkled (2-)2.5-5.5 mm; lfts 2-5 pairs, scarcely or little accrescent distally, broadly oblong, ovate-oblong or oblong-elliptic, rarely asymmetrically ovate-suborbicular, always obtuse or emarginate, at base inequilaterally rounded or cordate on both sides, the distal pair ±4-10 x 1.5-7 cm, 1.1-2.6 times as long as wide, the margins plane, often sharp-edged beyond the marginal nerve, the straight subcentric mid-rib scarcely or not elevated above, cariniform beneath, the ±8-13 pairs of major camptodrome with intercalary secondary veins and tertiary reticulation all sharply prominulous beneath, often almost as emphatic above but there sometimes subimmersed. Peduncles incurved-ascending 2.5-10 cm; racemes loosely (6-)10-35-fld, the axis becoming 3-12(-16) cm, the fls in bud elevated above those expanded; bracts (caducous, little known) ovate- or lance-acuminate ±4-5 mm, membranous-margined; pedicels (at and after anthesis) 1.5-4 cm, charged laterally, well above middle, with a sessile or substipitate ovoid or ellipsoid gland 0.7-1.4 mm; buds plumply ovoid-ellipsoid very obtuse glabrous; sepals subpetaloid, at middle yellow, greenish or red-tinged, hyaline-margined, strongly graduated, all obovate concave, the small outer ones 4.5-8.5 mm, the largest inner one 14-21 mm; petals yellow glabrous, finely brown-veined when dry, subhomomorphic except the banner a little smaller and 2 abaxial ones a little larger and more oblique than the rest, all in outline obovate or obovate-flabellate beyond the slender claw, the adaxial ones ±20-25 mm, the larger abaxial ones 24-29 mm; androecium glabrous, the filaments of 4 median stamens 1.5-2.5 mm, of the central abaxial one 3.5-5.5 mm, of 2 lateral-abaxial ones (dilated, ribbonlike 1.2-1.8 mm wide) 10-13 mm, the anthers of 4 median ones 4.5-6.5 mm nearly straight subtruncate, the divaricate beak ±0.6-0.8 mm, of 3 abaxial ones lunately incurved with porrect beak ±0.8-1 mm, the body of the central one 6-8 mm, of its 2 neighbors 10-13 mm, the beaks of all 2-porose; ovary either glabrous or densely ascending-pilo- sulous; style straight filiform 5.5-6.5 mm, at apex symmetrically truncate and 0.3-0.5 mm diam; ovules 30-45. Pod declined at random angles, long persistent, the stout stipe 3-8 mm, the body in profile linear-oblong 8-20 x 1-1.4(-1.5) cm, straight or lunately decurved, piano-compressed, margined by the stout riblike straight or undulately constricted sutures, the stiffly chartaceous livid-castaneous, finally nigrescent valves finely transverse-venulose, scarcely elevated over seeds, the narrow but thick interseminal septa 3.5-5 mm apart; seeds (little known) narrowly oblong-ellipsoid compressed parallel to the pod-valves, 5.5-6 x ±2.5 mm, the testa castaneous lustrous finely minutely pitted, the smooth linear-elliptic areole ±3 x 0.5 mm.
Variety Key - Key to the Varieties of S. corifolia 1. Lfts 3-5 pairs, relatively narrow, (3.7-)4-9 x 1.5-4 cm, 1.8-2.6 times as long as wide; local but widespread in highland e.-centr. and s.-e. Goias and Sa. do Espinhago in n.-centr. Minas Gerais. 56a. var. caesia (p. 222). 1. Lfts 2 pairs, relatively broad, the distal pair ±5-10 x 4-7 cm, less than 1.5 times as long as wide; very local on headwaters of Rio Tocantins in centr. Goias. 56b. var. corifolia (p. 222).
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Discussion
Cassia corifolia was described by Bentham from a single flowering collection and placed provisionally in sect. Prososperma, its close affinity to C. (sect. Chamaesenna) reniformis going unrecognized. We now have pods of S. corifolia from the type-locality near Niquelandia in central Goias and these, like the seeds, the perianth with androecium, and especially the peculiar gland situated high on one margin of the compressed pedicels, are closely comparable only with those of S. reniformis. Our comprehensive description of S. corifolia includes not only the original plant of Bentham, still known from only one locality, but also the more widely dispersed Cassia caesia Harms, unknown to Bentham, of which S. corifolia sens, str. appears to us to be little more than a striking local variant differing in the fewer broader leaflets, but virtually identical in flower and fruit. In describing C. caesia, Harms repeated Bentham’s error in assessment of affinities, aligning his new species not among the chamaesennas where it properly belonged but with C. (sect. Prososperma) appendiculata (=S. (ser. Laxiflorae) australis (Veil.) Irwin & Barneby). For both Harms and Bentham the dilated reniform stipules were no doubt a decisive factor.