Senna pallida var. palmeri (Britton) 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 pallida var. palmeri (Britton) H.S.Irwin & Barneby

Type

Holotypus, US! isotypi, F (2 sheets), NY = NY Neg. 9396, US (2 sheets)!-Non Cassia palmeri Wats., 1887.

Synonyms

Peiranisia palmeri Britton

Description

Variety Description - Arborescent shrubs 1-5(-8) m, with terete whitish annotinous and virgate, deeply sulcate hornotinous branchlets, thinly strigulose distally but the lfts glabrous, of firm texture and subglaucescent, the 2-fld racemes at first axillary to coeval lvs, ultimately corymbose-paniculate and ± exserted. Stipules linear-setiform 2-6 x 0.2-0.3 mm. Major lvs 5.5-12(-61) cm; petiole 16-40 mm, ±2-3 times as long as first segment of rachis; rachis (2-)2.5-8(-10) cm bluntly carinate dorsally; gland between proximal pair stipitate 1.4-2.8 mm, the body 0.5-1 mm wide; lfts 4-8(-9) pairs, the distal pair narrowly or broadly obovate obtuse or deltately subacute 15-25(- 30) x 7-12(-15) mm, 1.7-2.3 times as long as wide, simply pennmerved, the 5- 6 pairs of camptodrome secondary veins above fully immersed or almost so, beneath finely prominulous or merely discolored, subsequent venulation invisible. Peduncles 1.2-2.8 cm; pedicels 1.6-2.7 cm; long sepals 6.5-9.5 mm; long petals 2.4-3.1 cm; androecium glabrous, the filaments free, those of 4 median stamens 1.3-1.8 mm, of 3 abaxial ones 3.5-5 mm; anthers of 4 median stamens (as var. pallida) 4-6 mm, of 3 abaxial ones 5-7 mm, the beak (1.8-)2.2-3.5 mm. Stipe of pod 6-9 mm, the body 7-13(-15) x 0.65-0.8(-0.9) cm, the valves shallowly convex over seeds; seeds 3.1-3.7 x 1.8-3.1 mm, the areole 0.8-0.9 x 0.55-0.7 mm.-Collections: 9. [Key: "Appendage terminal of lf-stalk subulate or setiform, not modified and dilated into a gland; range of whole species.Continental N. and S. America and Lesser Antilles, s. Windward Is. and Swan Is. in s. Caribbean; anthers nearly always stouter (1.2-)1.3-2 mm diam, abruptly truncate at apex and the tubules there commonly umbonate at the angle opposed to the laterally divaricate, often slightly infra-terminal beak, if whole anther less than 1.25 mm diam and umbo pronounced. Reticulate tertiary venulation imperceptible or almost so on both faces of lfts, these superficially either penninerved or veinless. Lfts or larger primary cauline lvs 2-8(-9) pairs, perceptibly and usually conspicuously accrescent distally, the terminal pair longest; areole of seeds 0.4-0.9 mm in greatest diam. Scattered over s. Mexico and Guatemala. Plants of Pacific Mexico to Chiapas and highland Guatemala. Pod 6.5-9 mm wide; lowland Michoacan and Guerrero, in matorral at 0-800 m."]

Distribution and Ecology - Brushy flats and hillsides, from near sea-level behind the beach up to 800 m in the foothills, apparently local along the Pacific slope of Sa. Madre del Sur in Michoacan (n. of Playa Azul) and Guerrero (between rios Tecpan and Papagayo), and inland, in the hill-country w. of Iguala, Guerrero.-Fl. I-IV.

Discussion

The var. palmeri is in some ways intermediate morphologically between sympatric lowland var. pallida and allopatric upland var. quiedondilla, combining the relatively few pairs of leaflets of the former with the deeply sulcate young branchlets, the simply venulose leaflets, the corymbose-paniculate inflorescence and the broad pod of the latter. Although the pod is much wider (6.5-9 not 2.5-5 mm) than that of var. pallida, the seeds are not or scarcely larger and bear on the faces the same small areole. The strong resemblance in most technical features between var. palmeri and the Peruvian var. nemorosa, which has seeds of a size to match their pod, is no doubt due to convergent evolution.

Distribution

Michoacán Mexico North America| Guerrero Mexico North America|