Senna robiniifolia (Benth.) 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

Senna robiniifolia (Benth.) H.S.Irwin & Barneby

Type

Lectoholotypus (Britton & Killip, 1936, p. 181, by implication sub Peiranisia santanderensi): Wright 2370, collected (acc. original pencilled ticket at NY) from a tree cultivated at El Retiro, prov. Oriente, Cuba), K! = NY Neg. 1429: isotypi, G, GH, NY!-P

Synonyms

Cassia robiniifolia Benth., Peiranisia santanderensis Britton & Killip, Peiranisia robiniifolia Britton & Rose, Peiranisia macrochlamys Pittier, Peiranisia santanderensis Britton & Killip, Adipera santanderensis Britton & Killip

Description

Species Description - Slender trees and arborescent shrubs 4-8 m, with terete striate or ribbed-canaliculate younger and strongly lenticellate annotinous branchlets, strigulose-pilosulous with forwardly subappressed and often some, less often mostly widely incurved-ascending, sometimes lutescent hairs up to 0.2-0.6 mm, the foliage bicolored, the lfts above dark green (brunnescent in drying) and either glabrous or puberulent-pilosulous, beneath paler and either glabrous, strigulose, or densely pilosulous, always ciliolate, the terminal or subterminal, basally leafy-bracteate but often distally leafless and exserted panicle composed of mostly 2- or 2-4-fld racemes. Stipules falcately linear-attenuate 4.5-11 x 0.2-0.45 mm caducous (lacking from fruiting spms). Lvs (disregarding reduced distal ones) 8-18(-24) cm; petiole including firm, moderately dilated pulvinus 1.5-3(-3.5) cm, at middle 0.6-1 mm diam, bluntly carinate-ribbed dorsally, openly grooved ventrally; rachis (3.5-)4.5-12(-14) cm; petiolar glands ascending from between all or several, exceptionally only the proximal pairs of lfts, stipitate or subsessile, (1.3-) 1.8-3.2 mm, the slender stipe either glabrous or puberulent, the glabrous, laterally compressed body 0.2-0.4(-0.7) mm diam, commonly incurved or even hamate distally; lfts (of major lvs) 5-9(-10) pairs, strongly accrescent upward, the ultimate pair elliptic or elliptic-oblanceolate, triangular- to deltate-acute or obtuse mucronate (2.5-)3-6 x 0.9-1.7(-1.9) cm, 2.5-4 times as long as wide, at base rounded on proximal and cuneate on distal side, the margin revolute, the straight centric midrib cariniform beneath, with (8-)9-14 pairs of major camptodrome secondaries finely prominulous usually on both faces, rarely only beneath, the reticular venulation prominulous either on both faces or only beneath. Peduncles 1.5-3 cm; racemes subumbellately or very shortly (l-)2-4-fld, the axis 0-5(-8) mm; bracts elliptic-oblanceolate concave 1.7-2.7 mm, very early caducous; glands at base of pedicels either 0 or random and caducous; pedicels 20-33 mm; buds subglobose glabrous or at base puberulent, the sepals sometimes ciliolate; sepals brownish with pale margins, strongly graduated, all broadly obovate-suborbicular, the inner 5-6.5 mm; petals yellow, puberulent dorsally along and often between the veins, 3 adaxial smaller, oblanceolate-obovate narrowed to slender claw, 1.2-2 cm, the 2 abaxial larger, one short-clawed and obovate- cordate, one subsessile reniform-scoop-shaped, the longer 1.5-2.4 cm; androecium glabrous; filaments of staminodia and 4 median stamens 1-2 mm, connate at base or up to middle, those of 3 abaxial ones free, 2-3 mm; anthers of 4 median stamens 3-4 mm usually bottle-shaped by constriction just below the very short divaricate beak which dehisces by one U-shaped slit, those of 3 abaxial ones 3-5 mm, contracted into a tubular porrect beak 1.8-2.5 mm slightly enlarged and 1-porose at apex; ovary strigulose-pilosulous; style 1-1.4 mm, ±0.2 mm diam; ovules 24-34. Pod obliquely ascending or pendulous, the stipe 4-8 mm, the linear compressed, slightly curved or straight body (8-) 10-16 x 0.55-0.75 cm, 2-carinate by the obtuse sutures, the papery atrocastaneous valves becoming low-convex over seeds, faintly transversely venulose, finally fragile and easily broken along lines of interseminal septa; seeds compressed-obovoid 2.8-4 x 1.6-3 mm, the pale brown testa sublustrous crackled, the elliptic areole 1.2-1.8 x 0.5-0.75(-l) mm.-Collections: 57.

Distribution and Ecology - Open woods, thickets, hedges, sometimes along streams, of highly discontinuous, montane and lowland dispersal in e. Cuba, Venezuela, n.-e. Colombia and Pacific lowland Ecuador, long cultivated and perhaps in some places naturalized: lowlands and foothills of e. Cuba (Oriente) from Holguin and Manzanillo s.-e. to s. foothills of Sa. Maestra, formerly cultivated at La Habana: Cauca valley and Cordillera Oriental of n. Andes at middle elevations (±850-2100 m) in Colombia (Antioquia, Norte de Santander and Santander) and adjoining Venezuela (Tachira); mountainous n. Venezuela at 1000-1700 m in Falcon (Sa. San Luis) and Distrito Federal (Parque del Avila and cultivated in Caracas); lowland n. Venezuela, perhaps only cultivated but status not recorded, in Lara (Barquisemeto) Yaracuy (Yaracuy) and Portuguesa (Upper rio Portuguesa); disjunct near 500 m on lower Paragua river near 7°N in Bolivar; again widely disjunct in lowland disturbed forest at 20-350 m in s.-w. Ecuador in Manabi (Porto Viejo, Manta) and Guayas (Guayaquil, Isla Pina, Pedro Carbo).-Fl. in Cuba (VII-)X-III, in Venezuela VII-XII, in Colombia III-V (but data doubtless incomplete), in Ecuador V-VII(-IX).

Discussion

Our concept of S. robiniifolia, embodied in the foregoing description, is essentially that of Bentham except as modified or amplified by a century of collecting; and dissents from that of Britton who believed the species to be endemic to Cuba. The Cuban material acquired since 1871 shows that Bentham’s key character of "4-10"-flowered racemes was mistakenly derived from a succession of 2-3-flow- ered ones, not of single flowers; in all modern collections the basic racemose elements of the inflorescence are mostly 2-flowered, only a few early ones becoming 3-4-flowered by elongation of the axis beyond the first pair of pedicels. In this respect, as in the union of the anterior filaments of the androecium, S. robiniifolia agrees with S. viciifolia (which see for comment and differential characters) and the distantly allopatric Central American S. tonduzii, different chiefly in the elliptic-acuminate, prominently venulose leaflets. The inflorescence, except for the 1-pored dehiscence of the four median anthers, is indistinguishable from that of polymorphic S. pallida which, however, within or near the range of S. robiniifolia, has shorter, proportionately wider leaflets, glands more persistent at insertion of the pedicels and fewer on the leaf-stalks, and a pod at once narrower (3-4.5, not 5.5-7.5 mm wide) and when ripe not fragmenting along lines of inter- seminal septa. The known range of S. robiniifolia is difficult to account for except under the supposition that it has been modified by man. In eastern Cuba, where even in the first instance it was seen by Charles Wright only as a cultivated tree, it is reported from the intensively settled and disturbed lowlands; conceivably it may be merely introduced in Cuba as an ornamental. It appears to be truly native in the northern Andes, but the few examples from this region are more densely pubescent than those from Cuba or Venezuela and can hardly represent the source of the Cuban plant. In Venezuela S. robiniifolia has been found in relatively cool mountain forest, in Falcon and near Caracas; in the hot, seasonally dry llanos of the upper Portuguesa River; near (or in) the cities of Yaracuy and Barquisimeto, where it may be only planted; and distantly disjunct on the Paragua fork of the Carom south of the Orinoco. The Ecuadorian populations differ slightly in the more obtuse leaflets and perhaps larger seeds (known from too few samples) and will perhaps deserve some form of taxonomic recognition. Careful observation in the field will doubtless contribute to a solution of this problem in plant geography. Senna robiniifolia was collected first in Cuba by Ramon de la Sagra (P, hb. A. Richard., nos. 13311 and 231/7).

Common Names

Urquia , orimaco

Distribution

Oriente Cuba South America| Antioquia Colombia South America| Norte de Santander Colombia South America| Santander Colombia South America| Táchira Venezuela South America| Falcón Venezuela South America| Distrito Federal Venezuela South America| Lara Venezuela South America| Yaracuy Venezuela South America| Portuguesa Venezuela South America| Manabí Ecuador South America| Guayas Ecuador South America|