Senna pallida var. pallida

  • Title

    Senna pallida var. pallida

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Senna pallida (Vahl) H.S.Irwin & Barneby var. pallida

  • Description

    177a. Senna pallida (Vahl) Irwin & Barneby var. pallida. Cassia pallida Vahl, 1807, l.c., sens, restr.-"Habitat ad St. Martham [Colombia], von Rohr."-Holotypus, C (hb. Vahl.)! = IDC Microfiche 8/1.7.8/11/1 = NY Neg. 10483.

    Cassia discolor Desvaux, J. Bot. 3(2): 72. 1814.-"Habitat in Jamaica."-Holotypus, s. loc., P (hb. Desvaux.), as to lvs only, the attached pod alien.-Referred by Bentham, 1871, p. 555 to Cassia glauca, but the pod alone belonging there.

    Cassia venustula Humboldt, Bonpland & Kunth, Nov. Gen. & Sp. 6(qu): 352. 1824.-"Crescit locis aridis prope Cumanam [Sucre, Venezuela]."-Holotypus, labelled "n. 529. Cumana," P-HBK! isotypus, B (hb. Willd. 7959)!Cassia acapulcensis Humboldt, Bonpland & Kunth, Nov. Gen. & Sp. 6(qu): 353. 1824.-"Crescit prope Acapulco Mexicanorum [Guerrero]."-Holotypus, P-HBK! isotypus, B (hb. Willd. 7970/5)!Cassia xiphoidea Bertoloni, Nov. Comment. Acad. Sci. Instituto Bonon. 4: 415. 1840.-"Habitat in Volcan de Pacaya [dept. Amatitlan, Guatemala] . . . Velasquezius dedit nomine Cassia species nova decussata."-No typus known to survive, but the description and locality persuasively suggest some pubescent phase of var. pallida.

    Cassia pallidior Rose, J. Wash. Acad. Sci. 17: 167, quoad typum, paratypis costaricensibus exclusis. 1927.-"Type . . . [US] 676583, collected by H. Pittier near Alajuela, Panama, January, 1914 (no. 2343) . . -Holotypus, US! isotypus, NY!

    Peiranisia deamii Britton ex Britton & Rose, N. Amer. Fl. 23(4): 261. 1930.-"Gualan, dept. Zacapa, Guatemala, January 14, 1905, Charles C. Deam 291."-Holotypus, NY! isotypus, MO!-Cassia gualanensis Lundell, Carnegie Inst. Wash. Publ. 478: 212. 1937 (non C. deamii (Britton & Rose) Lundell, 1937).

    Peiranisia velutina Britton & Killip, Ann. N.Y. Acad. Sci. 35(3): 181. 1936.-"Patia Valley, Narino, Colombia, 200-500 m altitude, [F.C.] Lehmann B.T. 822 . . ."-Holotypus, NY! clastotypus (fragm), US! paratypi, Lehmann 7792, F, K; Lehmann B.T. 827, NY!

    Potentially arborescent shrubs at anthesis (0.6-)l-3(-4) m, with ribbed but usually not deeply sulcate annotinous branchlets, highly variable in pubescence, either glabrous to (sometimes including) the ovary or thinly to densely pilosulous with forwardly incumbent or spreading, pallid or rarely lutescent hairs to 0.3- 0.8(-1.3) mm, the bicolored lfts glabrous on both faces, puberulent beneath and ciliolate, or pilosulous overall, the inflorescence when young consisting of simple 2-fld racemes axillary to coeval lvs, in age often becoming ± paniculate and exserted.

    Stipules linear-lanceolate or -oblanceolate 3-9(-11) x 0.3-1(-1.2) mm, carinate dorsally.

    Major lvs 5-15(-18) cm; petiole (7-)9-22 mm, 1-2.8 times as long as first interfoliolar segment of rachis; rachis (2-)2.5-8(-10.5) cm; glands between proximal 1-3 pairs of lfts, stipitate or sessile, the lowest 1.5-3.5 mm, the ovate acute or elliptic compressed body 0.4-1.2 mm wide; lfts commonly 5-8, rarely in none more than 4 or in some up to 9-10(-11) pairs, accrescent upward along rachis, the distal pair mostly obovate obtuse mucronulate, sometimes oblanceolate obtuse or abruptly deltate-acute, 18-42(-53) x (5.5-)7-21(-22) mm, 1.5-3.3 times as long as wide, the venation of 5-9(-11) pairs of camptodrome secondary veins nearly always finely prominulous (exceptionally shallowly engraved) on upper face, always so beneath, there giving rise to a well defined tertiary reticular venulation either prominulous or if almost immersed strongly defined by color.

    Peduncles (7-)9-22(-27) mm; racemes mostly 2-, rarely some 3-4-fld, the pedicels (9-) 11-23 mm; long sepals (5.5-)6-10(-11) mm; long petals (pubescent or rarely glabrous dorsally) (15-)17-27(-29) mm; filaments glabrous or puberulent, those of 4 median stamens ± dilated free 0.8-1.8 mm, those of 3 abaxial ones 2.2-4.5(-5) mm, the anthers of 4 median stamens 2.8-5.3 mm, abruptly truncate, the lateral beak ±0.2-0.4 mm, those of 3 abaxial ones 4-6.4 mm, the beak (1.4-) 1.6-3 mm; ovary commonly strigulose, rarely glabrous or pilose; style 1.2-2.4 mm.

    Stipe of pod 2.5-7 mm, the body (5-)6-12(-15) x (0.25-)0.33-0.45(-0.5) cm, the ripe valves raised over each seed as a distinct 4-armed pyramid; seeds 2.33.5 x 1.5-2.8(-3) mm, the areole 0.4-0.8 x 0.4-0.8 mm.-Collections: 434.-Fig. 11 (androecium).

    Forest borders and clearings, glades in deciduous woodland, brushy hillsides, benches of barrancas, stream-banks and savanna thickets, thriving in disturbed habitats and becoming locally weedy along highways and in hedges, widely dispersed, mostly in xeromorphic plant-communities, from sea level up to 1100 m, exceptionally higher (in Michoacan to 1440, in Guatemala to 1480, in Honduras and Nicaragua to 1200 m), over much of extreme n. South and Central America and the tierra caliente of s. and s.-w. Mexico, there extending on the Gulf slope to Veracruz (but absent from Yucatan Peninsula) and on the Pacific slope to Sinaloa and the Cape region of Baja California Sur, in Colombia s. in inter-Andean valleys to Rio Patia in Cauca and Narino, e. through Caribbean Venezuela to Nueva Esparta and the Windward Islands (Grenada; Martinique, perhaps introduced); Swan Islands in the w. Caribbean; one station in the middle Orinoco drainage in Guarico, Venezuela; apparently much isolated in savannas of n. Territorio do Roraima, Brazil.-Fl. abundantly X-IV, sporadically throughout the year, in dry seasons often from brachyblasts with greatly diminished foliage.- Abejon; vara prieta; flor de San Jose (Mexico, Central America); montenegro (Costa Rica); brusca; giiereguere (Venezuela).

    This is the common lowland continental phase of S. pallida characterized by relatively few (commonly 5-9, rarely up to 11) pairs of distally accrescent leaflets intricately reticulate beneath and by a narrow pod with valves raised when ripe over each seed in the form of a four-armed pyramid. It is dispersed over the whole range of the species short of Peru, extratropical northwestern Mexico, Yucatan and the Bahamas, where it is replaced by closely analogous forms differing in simpler venulation of the leaflets commonly associated with a pod simply mounded over each seed. The var. pallida varies much in amplitude of the leaflets and flowers, the variation due partly to seasonal or climatic influences and partly, no doubt, to genetic control (not experimentally demonstrated); and conspicuously in pubescence, as described in our discussion of S. pallida sens. lat. The holotypi of Cassia pallida, C. pallidior and C. acapulcensis represent glabrate or glabrescent, those of C. xiphoidea (probably) and Peiranisia deamii moderately pilosulous, and that of P. velutina densely pilosulous states. In a general but imprecise fashion our var. pallida is equivalent to the C. biflora of floristic works covering the northern periphery of South America, Central America, and Mexico.

    The identity of C. xiphoidea listed in the synonymy of var. pallida was obscure to Britton & Rose who mentioned it (1930, p. 268) nevertheless as a doubtful member of genus Peiranisia. No typus has survived in Bertoloni’s herbarium at Bologna (1977) and unless a duplicate can be found the name can be interpreted only through the description. This agrees very well with our concept of pilosulous Guatemalan var. pallida, especially in characterization of the pod as swordshaped and torulose (i.e. expressed over the seeds) and in the telling adjective decussata quoted from the collector Velasquez, which we interpret as a reference to the sharp X-shaped pyramidal form of each torulose segment of the pod valves.