Senna peralteana (Kunth) 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 peralteana (Kunth) H.S.Irwin & Barneby

Type

Holotypus, labelled simply "Campeche," P-HBK!-Gaumerocassia peralteana (Humboldt, Bonpland & Kunth) Britton & Rose, N. Amer. Fl. 23(4): 253. 1930, quoad nom., vix aliter.

Synonyms

Cassia peralteana Kunth, Gaumerocassia peralteana (Kunth) Britton, Cassia anisopetala Donn.Sm., Pseudocassia anisopetala (Donn.Sm.) Britton & Rose, Pseudocassia petensis Britton & Rose, Cassia petensis (Britton & Rose) Standl.

Description

Species Description - Precociously flowering shrubs 1.5-5 m becoming in forest or at forest margins woody vines, the annotinous and older branches gray, erratically lenticellate, often but not always armed at the nodes with ligneous aculeiform stipule-bases (described below), the short leafy unarmed annotinous branchlets like the foliage and axes of racemes villosulous with weak spreading-incurved or contorted simple hairs to 0.25-0.55 mm, the lf-stalks at insertion of petiolules and the raceme- axes in addition charged with rufescent, irregularly branched trichomes, the simple vesture at first yellowish, gray in age, the foliage strongly bicolored, above ± lustrous dark green (brunnescent in age or drying), thinly pubescent when mature, beneath dull, densely villosulous, the contracted subcorymbose panicle of erect or pendulous racemes leafy-bracteate, not or scarcely exserted, its main axis continuing to grow out during maturation of the fruit. Stipules subulate 1-2.5 mm, rather firm but deciduous, their base during the second year often but not invariably transformed into ligneous conic or spreading- decurved and prickle-like thorns (1.5-)3.5-6 mm seated on a ± dilated pediment. Lvs (7-) 10-21 cm; petiole slender including livid pulvinus (1.5-)2-4(-5) cm, at middle (0.55-)0.7-1.5 mm diam, narrowly shallow-sulcate ventrally; rachis (1-)2-8(-9.5) cm, its longer interfoliolar segments 1-2.6 cm; petiolar gland 0; pulvinules 2-4.5(-5) mm; lfts 2-5, of most mature lvs 3 or 4 pairs, accrescent upward, the distal pair broadly elliptic, elliptic-obovate or obovate obtuse apiculate or deltately acute-acuminulate (3-)4-8 x (1.5-)2-4 cm, 1.8-2.7 times as long as wide, at base subsymmetrically broadly cuneate (rounded), the margin revolute, the centric straight midrib shallowly canaliculate above, cariniform beneath, the 6-10 pairs of camptodrome secondary, the connecting tertiary and the open irregular reticular venules all finely prominulous above, more sharply so beneath; proximal pairs of lfts either like the distal pair only shorter, or at once shorter and broader, becoming obovate. Racemes incurved-ascending from axis, loosely 7-35-fld, several fls reaching anthesis together and these in the earlier stages of the raceme standing well below the at first erect, later nodding, serially racemose fl-buds, the axis including short peduncle becoming (4-)5-18 cm; bracts lance-subulate 1.5-2.8 mm caducous; pedicels at full anthesis filiform 9-19 mm, bracteolate at or above middle, the caducous bracteoles subulate 0.4-1.2 mm; buds globose when very young, thinly pilosulous, but the often dorsally glabrous ciliolate inner sepals early emergent; sepals separating long before true anthesis, submembranous yellowish, brunnescent when dry, well graduated, the outermost 3-4 mm, the innermost concavely obovate-suborbicular 5-5.5 x 2.6-4 mm; petals yellow drying brown or brownish-yellow, except for sometimes remotely pilosulous claw glabrous, when fully expanded highly heteromorphic, 4 alike except for size, beyond claw oblong or oblong-obovate, the 3 adaxial 4.5-8 mm, one abaxial 9-13 mm, the fifth petal asymmetrically oblong-ovate or dimidiately ovate, strongly incurved and folded over the androecium, measured along the arcuate midrib 16-20 mm; androecium functionally 7-merous, the fertile stamens isomorphic, their glabrous filaments 1-2 mm, the oblong, almost straight, dorsoventrally compressed anthers 3-3.6 x 1.3-1.4 mm, sulcate lengthwise only at the connective, bluntly truncate at apex and turned through ±90° into the separated lateral very short beaks, these opening by vertical slit; ovary linear-falcate glabrous; style ±1.5 mm, gently incurved, conic at tip; ovules ±50-66. Pod pendulous, the stipe 4-6 mm, the elongately linear body 20-36 x 1.2-1.6 cm, piano-compressed, ±2 mm thick at the strong sutures, the flat lignescent valves differentiated into a paler internally pithy margin running parallel to the sutures which becomes transversely cracked in ripening and an atrocastaneous face irregularly coarsely venulose, the interseminal septa very narrow or subobsolete, the seed-cavity ±5 mm long, extending only to the thickened valve-margin; seeds transverse, oblong-ellipsoid compressed parallel to the valves, ±5-6 x 3-3.5 mm, the lustrous smooth brownish-ochraceous testa marked on each broad face with an oblong-elliptic areole ±3.5-4 x 1.5 mm.-Collections: 33.

Distribution and Ecology - A vine of high forest or riverine forest, surviving as a diffuse shrub in thin savanna woodland or disturbed forest, reported from calcareous and serpentinized lateritic soils, 10-550 m, widespread over the Gulf lowlands and low hill- country from n.-w. Campeche (Laguna de Terminos) to Quintana Roo, s. in Mexico to n. Chiapas, thence s. into n.-e. Guatemala (Peten, Alta Verapaz, Izabal) and Belize (Belize and Cayo districts).-Fl. mostly II-VI, the fruit maturing slowly and long persisting.

Discussion

Senna peralteana is closely related to S. atomaria, differing constantly in the more prominently venulose upper face of leaflets, the minutely bracteolate pedicels unique in Senna, and the broader pod 12-16 (not 8.5-12, exceptionally 14) mm wide. The enlarged thornlike stipule-bases, either conic or curved backward like those of Amazonian S. spinescens, are a conspicuous feature of some specimens and lacking in others. The species is plastic in growth-form and one might expect in theory to find stipules adapted to climbing in the forest liana and perhaps absent from the juvenile shrubby state, but this is not the case; for example Jones & Facey 3344 (NY) from a liana 30 m long is thornless through growth of at least three consecutive seasons, whereas the low-shrubby Croat 23347 (NY), fruiting at 1.5 m, has short conic vulnerant thorns on annotinous branchlets. These thorns are not directly modified stipules but are formed by secondary thickening of the pediment to the real stipules, which are always small and caducous. The cause of apparently random development of thorns at some but not all nodes of a stem, in some but not all plants of S. peralteana, is a subject for field inquiry. The typi of Pseudocassia petensis and Cassia anisopetala are flowering specimens and the two species were doubtless referred by Britton & Rose to genus Pseudocassia, the first without reservation, the second provisionally, because of similarities in the asymmetric perianth and isomorphic anthers. They differ slightly in outline of leaflets, but are certainly conspecific. The only fruiting specimen of S. peralteana known to Britton, Lundell 1027 (NY, received several years after publication of the monograph in 1930), was annotated by Britton as an undescribed Isandrina, the affinity to S. atomaria being expressed in the pod. Bentham knew Cassia peralteana only from the typus, acquired by Bonpland from "celeber Peralta," whom we suppose to be the Mexican botanist Francisco Peralta y Guzman, mentioned in the bibliography of I. K. Langman (1964, q.v.). The epithet was transferred by Britton to a form of our Senna racemosa and therefore to the genus Gaumerocassia.

Common Names

Kanchinaik , mayahua

Distribution

Campeche Mexico North America| Quintana Roo Mexico North America| Chiapas Mexico North America| Petén Guatemala Central America| Alta Verapaz Guatemala Central America| Izabal Guatemala Central America| Belize Belize Central America| Cayo Belize Central America|