Senna nicaraguensis

  • Title

    Senna nicaraguensis

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

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

  • Description

    149.  Senna nicaraguensis (Bentham) Irwin & Barneby, comb. nov. Cassia nicaraguensis Bentham, Trans. Linn. Soc. London 27: 552. 1871.—"Tropical America, Mexico, and Central America, Seemann, Oersted. "— Lectoholotypus, ticketed "In provincia Segovia, Nicaragua, 1851, (Ersted, Cassia no. 37." K (hb. Benth.)! = NY Neg. 1421 \ paratypus, (Ersted, Cassia no. 38, K (hb. Benth.)!—Chamaesenna nicaraguensis (Bentham) Britton & Rose, N. Amer. Fl. 23(4): 250. 1930.

    Cassia seleriana Harms, Bull. Herb. Boiss. 7: 551. 1899.—"Habitat in Mexico, in prov. Chiapas in fruticeto apud Tonala: Seller] n. 2065; et in Guatemala, in dept. Santa Rosa ad Frajanes in 1000 m altitud.: J. Donn[ell] Smith n. 6116 (leg. Heyde et Lux)."—Lectoholotypus, Seler 2065, presumably †B; isotypi, GH, K!—Correctly equated with C. nicaraguensis by Standley, Contrib. U.S. Nat. Herb. 23: 411. 1922.

    Cassia nicaraguensis sensu Schery, 1951, p. 51, fig. 151.

    Amply leafy arborescent shrubs at anthesis 1.5-7(-9) m, with stout subterete smooth or in age lenticellate branches clothed when young with large herbaceous semicordate stipules, except for sometimes minutely residually puberulent lf- stalks and (exceptionally) dorsal face of lfts glabrous throughout, the long pluri- foliolate lvs sublustrously olivaceous either concolorous or slightly paler beneath, the inflorescence terminal paniculate, the panicle either leafy-bracteate or naked distally but not much exserted from foliage, the young racemes terminating in a blunt cone of imbricated petaloid bracts.

    Stipules early caducous (present only to early anthesis, absent from fruiting spms), dimidiately cordate-acuminate 10-35 x (6-)7-18 mm, the plane blades amplexicaul by their obtuse, greatly dilated contrapetiolar basal angle, flabellately many-nerved from base, reticulate distally, the midrib falcately curved outward into an acute or caudate apex.

    Lvs (disregarding depauperate ones in inflorescence) 16-40(-52) cm; petiole including discolored but little dilated pulvinus 3-9 cm, at middle (1.2-)1.5-2.8 mm diam, bluntly trigonous, obscurely sulcate, the lf-stalk distally becoming more sharply trigonous and openly shallow-sulcate; rachis 8-36 cm, its longer inter- foliolar segments 10-21(-24) mm; petiolar glands 0; lfts (7-)9-17(-19) pairs, subequal or a little accrescent upward, ascending from rachis face upward on turgid, dorsally keeled, when dry wrinkled pulvinule (1-) 1.4-2.8 mm, in outline varying (sometimes on one lf) from elliptic-, lance- or ovate-oblong to elliptic-oblanceo- late, the larger (3.5-)4-8 x 1-2.8 cm, all either obtuse or deltately subacute and abruptly mucronate by the costa excurrent by (0.5-) 1-3 mm, at asymmetric base broadly cuneate to shallowly cordate on proximal side, cuneate to rounded on distal one, the margin plane, the slender straight centric midrib cariniform beneath, less prominent or immersed above, the 10-16(- 19) pairs of major camptodrome (with random intercalary) secondary veins and fine tertiary and reticulate venulation prominulous on both faces, the ultimate defined areoles of dorsal one much < 1 mm diam.

    Racemes incurved to vertical, at first densely soon loosely (8-)15-70-fld, the tapering axis becoming (6-)9-40 cm; bracts petaloid yellow or submembranous brownish-yellow, obovate-cuneate or broadly obovate obtuse 18-25 mm concave, enveloping the young fl-buds, thrown off as the pedicel begins to elongate; pedicels at full anthesis and afterward ascending 12-21 mm; buds obovoid-ellipsoid obtuse; sepals submembranous yellowish, orange or brownish, little graduated, all broadly obovate or oblong-obovate obtuse, the innermost (13-) 14-21 mm; petals (glabrous) yellow drying pale or stramineous, strongly arborescently brown-venulose, all obovate or oblong-obovate contracted at base into a slender claw, little heteromorphic except the vexillary one sometimes broadest, the longest 16-28 mm, commonly 1/3 longer than sepals, sometimes scarcely exserted; androecium glabrous 4-morphic: 3 adaxial staminodes with cordate blades; 4 median stamens with filaments 2-3.5 mm, anthers oblong, slightly incurved, the body 4-5 mm, contracted into a porrect truncate beak ±1 mm; 1 sterile abaxial stamen opposed to the vexillum, cruciform, the basal tails of the anther-sacs divaricate at nearly 90°; on either side of the last 2 long stamens with filament 5.5-7 mm, the anthers linear-oblong, strongly dorsoventrally compressed, incurved through 1/3 circle, (10.5-)11-18 mm, truncate at apex and produced as an obscure divergent beak ±0.5 mm; ovary glabrous; style filiform, hamately incurved at tip, 6.5-8.5 mm; ovules (15-) 18-32(-35).

    Pod randomly spreading-declined from stiff arched pedicels, short-stipitate, the stipe 3-6 mm, the linear-oblong, strongly flattened body 7-12.5 x 1-1.9 cm, bicarinate by the sutures, at base cuneately contracted into stipe, at apex more abruptly rounded-truncate into the small persistent style-base, the thin reddish- green or atropurpureous valves becoming papery lustrous, finely transverse-venulose, expressed over each seed in the form of an obtuse mound, these elevations forming a pronounced crest down the length of the valve; dehiscence through both sutures, inert; seeds uniseriate compressed-pyriform or subrhombic-pyriform 4-4.7 x 2.1-2.6 mm, on each face above the areole elevated into a mound conformable with the external protuberances of the valves, the ochraceous sub- lustrous testa rugulose-reticulate, the elliptic smooth areole 1.1-1.3 x 0.5-0.9 mm.—Collections: 62.—Fig. 11 (androecium), 13 (pod, seed).

    Dry and seasonally moist mixed forest, tropical deciduous forest, disturbed woodlands and thicket remnants of forest, sometimes abundant locally in disturbed habitats along streams and highways, 30-1200 m, interruptedly dispersed between Panama Canal and s. Mexico, chiefly along the Pacific foothills and coastal plain, but reaching the Caribbean slope in w. Honduras and adjoining Guatemala and the Gulf slope in centr. Chiapas, in Mexico scattered along the seaward slope of Sa. Madre del Sur from Istmo de Tehuantepec to w. Jalisco.— Fl. IX-XII(-IV), fr. XI onward.—Huevo de iguana (Chiapas).

    A handsome tall shrub or bushy treelet that deserves the attentions of gardeners in monsoon climates, S. nicaraguensis is recognized, in the context of sect. Senna, at anthesis by broad foliaceous, dimidiately cordate-amplexicaul stipules and petaloid bracts shielding the young flower buds, and in fruit by the lustrous, narrowly oblong, umbonately crested pod. These features, seldom coetaneous, coincide with long narrow multifoliolate leaves that are characteristic in the range of the species. In S. nicaraguensis the crest running lengthwise along the pod’s valves is composed of simple mammillate cones raised over the seeds; in allied Brazilian S. martiana, similar in foliage and petaloid bracts but different in the narrow stipules, these projections are keeled both vertically and transversely and take the form of T-shaped studs. The Mexican S. centranthera resembles 5. nicaraguensis in form and ornamentation of the pod but differs in the narrow stipules and yet more numerous, smaller leaflets. Where the ranges of this pair overlap in southern Mexico they are separated by life-zone and altitude.