Senna velutina (Vogel) 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 1: 1-454.

Family

Caesalpiniaceae

Scientific Name

Senna velutina (Vogel) H.S.Irwin & Barneby

Type

Holotypus, presumably †B, not seen; neoholotypus, Martius Herb. 220, K! = NY Neg. 1459; isotypus, NY!

Synonyms

Cassia velutina Vogel, Cassia dysophylla Benth.

Description

Species Description - Coarsely leafy, erect or diffusely ascending, weakly woody shrubs of rapid growth, at anthesis 1-3 m, densely silky-pilose or -tomentulose throughout, except for sometimes glabrous upper face of lfts, with fine mostly sinuous or entangled, subappressed or partly spreading hairs to 0.5-1.5 mm, the vesture of inflorescence, pods and often of distal (sometimes all) lvs rufous, the foliage bicolored, the lfts above brownish-olivaceous dull or (when glabrous) lustrous, paler beneath, the many-fld racemes of large fls axillary to distal lvs or subpaniculate, not or only shortly exserted from foliage. Stipules sometimes persistent, but usually deciduous before the associated lf, (10-) 15-35(-55) mm long, varying from falcately semi-lanceolate-caudate and expanded only at base on exterior side of midrib to broadly semi-cordate-acuminate or caudate with obliquely descending amplexicaul obtuse auricle and a blade expanded on both sides of midrib, the blade at broadest part (2-)3-16(-27) mm wide. Lvs (small distal ones disregarded) 11-28 cm; petiole including little differentiated pulvinus (1.2-)1.5-3.2(-4) cm, at middle 1.4-3 mm diam, rounded dorsally, openly shallow-sulcate ventrally; rachis 5-11(-14.5) cm; glands between all pairs of lfts, shortly stipitate or sessile 1.6-3 mm, the stipe when present pilosulous, the body in profile mostly lanceolate acute, sometimes ovate obtuse, 0.4-0.8 mm diam; pulvinules 2.5-4.5(-5) mm; lfts 3-6, in most lvs 3 or 4 pairs, accrescent distally, mostly oblong-, lance- or oblance-elliptic, less often ovate, oblong or obovate, at apex triangular, deltate or obtuse, commonly mucronulate or caudate- acuminulate, the distal pair 4.5-11 x (1.5-)2-4.4(-5) cm, (2-)2.2-3 times as long as wide, at base inequilaterally rounded or subcordate, the margins obscurely revolute, the centric midrib and (9-) 10- 16(- 18) pairs of widely ascending secondary nerves immersed above, prominulous or cordlike beneath, the secondaries mostly more densely rufous-pilosulous than the intervenium, camptodrome only close to margin of blade, the tertiary venulation faint or fully immersed. Peduncles stout incurved-ascending 2-8 cm; racemes mostly (6-)10-50-fld, the axis becoming 5-26 cm, the buds elevated above level of at least the earlier fls; bracts deciduous from swelling buds, broadly lance- or ovate-acuminate, acute or caudate (4-)5-11 (- 15) mm; pedicels at and after anthesis 17-37 mm, subtended laterally at base by a hornlike (sometimes deciduous, often eaten) gland 1.5-2.5(-3) mm; buds obliquely obovoid, densely rufous-pilosulous; sepals except for sometimes glabrate submembranous margins firm and pilosulous dorsally, broadly obovate, ovate-elliptic or orbicular, strongly graduated, the smaller outer one 6.5-11.5 mm, the largest inner one 13-18 mm; petals yellow, when dry delicately brown-veined, all pubescent dorsally, the 3 adaxial subsymmetrically ob- ovate-flabellate, the banner often emarginate, these 17-25 mm, the 2 abaxial slightly longer and more oblique, mostly 25-35 mm; filaments pilosulous or puberulent, those of 4 median stamens 1-3 mm, of the central abaxial ones 5-8 mm, of the two latero-abaxial ones dilated (1-1.6 mm wide) 7-12 mm, the anthers glabrous or rarely puberulent in the grooves, those of 4 median ones (in two slightly graduated sets) straight or almost so, (4-)5-8.5 mm, with obliquely divaricate beak 0.4-0.7 mm, that of the centric abaxial stamen slightly incurved 7-10.5 mm, those of 2 latero-abaxial ones lunately incurved 10.5-15.5 mm, the beaks of the 3 abaxial anthers not over 1 mm long, obliquely truncate, those of all anthers 2-porose; style 3.5-5 mm, straight linear, truncate at apex, 0.25-0.4 mm diam; ovules 22-45. Pod declined at random angles, often persisting through a full season on annotinous branchlets, the stipe 2-5 mm, the narrowly linear body simply or sigmoidally decurved (10-) 12-22 x 0.3-0.4(-0.45) cm, compressed-quadrangular, carinate by the thick sutures and by a rib running the length of the valves a trifle closer to the dorsal than to the ventral suture, the stiffly papery, densely rusty-pilosulous or -strigulose valves scarcely raised over seeds but marked at the interseminal septa by shallow transverse sulci, these distant 4-7 mm; seeds vertically aligned along pod, in outline oblong or obtusely rhombic (3-)3.3-4.2 x 1.7-2.4 mm, the testa lustrous olivaceous or brown smooth, the oval or elliptic areole 1-1.5 x 0.4-0.8 mm.—Collections: 49.—Fig. 9 (petiolar nectary), 22 (pod).

Distribution and Ecology - Cerrado, usually in red sandy soils, becoming locally abundant in disturbed environments, sometimes forming extensive thickets along roadsides, (200-)400-1050 m, common and widespread over the Brazilian Planalto w. of Rio S. Francisco, from the middle Tocantins valley in Goias w. to the sources of Rio Xingu in Mato Grosso, thence s. through Goias to the upper Paracatu and Pa- ranaiba in w. Minas Gerais, and s.-w. through centr. and s. Mato Grosso just into centr. Paraguay and s.-e. Bolivia; disjunct on Rio Mogi-guaçu in centr. Sao Paulo (mun. Sao Carlos), and remotely so on savannas of upper Mazaruni River in Guyana and along middle Orinoco River in Amazonas, Venezuela.—Fl. (I-)II-VI.

Distribution

Goiás Brazil South America| Mato Grosso Brazil South America| São Paulo Brazil South America| Guyana South America| Amazonas Venezuela South America| Paraguay South America| Bolivia South America|