Senna cuatrecasasii 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 1: 1-454.
-
Family
Caesalpiniaceae
-
Scientific Name
-
Type
Holotypus, F (2 sheets, nos. 1303907. fl, 1303906, lf); clastotypus (fragm), NY; isotypus, US.
-
Description
Species Description - Shrubby ± sarmentose to 1 m (ultimate potential stature unknown) with terete purplish-brown, minutely puberulent annotinous branchlets and notably ample chartaceous bicolored lfts, these above glabrous olivaceous scarcely lustrous, beneath yellowish-green and densely minutely pilosulous, the inflorescence composed of leafless panicles of densely many-fld racemes arising from axil of living lvs and much shorter than them. Stipules unknown, doubtless early deciduous. Lvs 4-5 dm; petiole including discolored wrinkled pulvinus 6.5-10 cm, at middle 3-4 mm diam, subterete, very narrowly obscurely 2-ridged ventrally, the sulcus hence shallow and open; rachis 5.5-7 cm, slightly shorter than petiole; glands 1 or 2 at each pair of lfts sessile, plumply ovoid obtuse 3-6 mm; pulvinules 1.3-1.5 cm, discolored; distal pair of lfts broadly ovate-elliptic, at apex abruptly acuminate, 28-35 x 14-18 cm, at base asymmetrically rounded (at very base decurrent into pulvinule), the margin revolute, the straight centric midrib with ±14-15 pairs of major secondary veins weakly prominulous above, sharply so beneath, the tertiary and subsequent fine reticular venulation scarcely raised above, weakly and bluntly so beneath, the intervenium and reticular venules densely minutely papillate; proximal pair of lfts similar, ±2/3 as long. Axis of the panicle 1-4 cm, purplish-brown and densely minutely pilosulous; racemes 30-100-fld, the axis becoming 5-17 cm; bracts ovate ±1 mm, deciduous from the very young bud as pedicel begins to elongate; pedicels at anthesis ±10-12 mm, to 18 mm in fruit; buds subglobose, opening before true anthesis, puberulent below middle; sepals submembranous, perhaps reddish when fresh, scarcely graduated, broadly elliptic obtuse 5.5-6.5 x 3.5-4 mm, delicately 3-nerved from base, the nerves not or only faintly branched distally, not reticulately anastomosing toward apex; petals (presumably yellow, when dry pinkish- brown) puberulent dorsally, subisomorphic, elliptic-oblong beyond short claw, 12-14 x 6—6.5 mm; functional stamens 7 subisomorphic, the puberulent filaments 1.5-2 mm, the purplish-brown glabrous anthers including the short oblique 2- porose beak 5.2-5.7 mm, the beak of the 3 abaxial ones only a trifle longer than that of the 4 median ones and hardly more porrect; ovary puberulent; style claviform incurved, 0.9-1 mm diam just below the hollow stigmatic orifice, this 0.5 mm diam; ovules (1 count) 76. Ripe pod unknown, when half ripe ±15 cm, the brown valves densely papillate.—Collection: 1.
Distribution and Ecology - Habitat not recorded, known only from the type-locality, near 25 m alt. in the first foothills of the Pacific slope of Cordillera Occidental near 3°45'N in Valle de Cauca, Colombia.—Fl. ±X-XII.
-
Discussion
Although as yet only dimly known through the flowering type-collection, S. cuatrecasasii is easily distinguished from all described Bacillares in the combination of biglandular leaf-stalks, immensely ample leaflets papillate as well as pilosulous beneath, axillary panicles of many-flowered racemes and relatively small, short-pedicelled flowers. The leaflets suggest by their great size those of S. macrophylla, but this differs fundamentally in the syndrome of 1-glandular leaf-stalks, plane-margined and more sharply reticulate leaflet-blades, reticulately venulose sepals and much shorter, relatively few-flowered racemes, usually solitary in the axils. Senna huilana, known to occur also on the Pacific slope of the Western Cordillera, but at greater altitudes, may have leaflets almost as ample as those of S. cuatrecasasii, but the blades are glabrous on both faces, there is only one gland on the leaf-stalks, the larger flowers are borne on pedicels 2-5 (not 1-1.2) cm long, and the androecium is differentiated into two sets of strongly dimorphic members. Other Colombian Bacillares characterized by biglandular leaf stalks, S. trianae and S. quinquangulata, have leaflets at most 16 (not 28-35) cm long; the latter, which has been collected near the type-locality of S. cuatrecasasii, on Bahia Buenaventura (Cuatrecasas 19741, F), differs further in its exserted terminal panicle of racemes. The true affinities of S. cuatrecasasii within its series cannot be profitably discussed until the pod and seed become available for comparison. The one immature pod examined (US) has valves densely minutely verruculose like those of S. papillosa, but the surface when ripe cannot be foretold from the scant material at hand. It is a particular pleasure to associate this noteworthy Colombian Senna with the name of Jose Cuatrecasas, eminent student of the Colombian flora.
-
Distribution
Valle del Cauca Colombia South America|