Senna confinis (Greene) H.S.Irwin & Barneby
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Authors
Howard S. Irwin, Rupert C. Barneby
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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.
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Family
Caesalpiniaceae
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Scientific Name
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Type
Holotypus, ND? (not seen); isotypus, NY!—Earleocassia confinis (Greene) Britton ex Britton & Rose, N. Amer. Fl. 23(4): 249. 1930.
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Synonyms
Cassia confinis Greene, Earleocassia confinis (Greene) Britton
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Description
Species Description - Coarse malodorous, ultimately suffrutescent but precociously flowering and often short-lived herbs with 1-few stout stems erect or incurved-ascending from blackish roots, commonly 3-9(-11, said by Goldman, l.c., to attain 20) dm, densely subvelutinously pilose-pilosulous throughout with spreading-ascending, mixed shorter and (fewer) longer hairs up to 0.8-1.3 mm, the short vesture of stems ± retrorse, elsewhere ascending, the longer hairs all spreading-ascending and a few of them sometimes becoming setiform and up to 3 mm, the whole vesture yellowish when young, gray at maturity, the short few-fld racemes axillary to several successive lvs along the stem, the peduncles as long or longer than the lf. Stipules sinuously incurved or erect, linear-attenuate or setiform 3-9 x 0.3-0.9 mm, persistent to maturity of associated lf, ultimately dry deciduous. Primary cauline lvs 4.5-10 cm (of some axillary spurs, not further mentioned, smaller); petiole stout, including firm, little dilated pulvinus (1.4-) 1.8-4 cm, at middle 0.7-1.1 mm diam, obtusely carinate dorsally, widely shallowly sulcate ventrally; rachis 7-22 mm, its terminal appendage setiform retroarcuate; petiolar glands between all pairs, slenderly stipitate, in profile 1-2.6 mm tall, the stipe densely pilosulous, the slenderly fusiform reddish head shorter than stipe, 0.15-0.25 mm diam; pulvinules 1-2 mm; lfts of most lvs exactly 2, or few random lvs 1 or 3 pairs, the distal pair largest, these broadly elliptic or obovate (ovate)- elliptic obtuse mucronate (apiculate) 2-4.7 x 1.2-2.7 cm, 1.4-2.1 times as long as wide, at base broadly cordate proximally, rounded or broadly cuneate distally, the margin plane, the midrib and 5-7 pairs of secondary veins prominulous beneath only, tertiary venulation fully immersed; smaller proximal lfts either similar in outline or proportionately broader. Peduncles stiffly ascending (3.5-)4-9 cm; racemes shortly or subumbellately 3-10-fld, the axis becoming 3-20(-30) mm; bracts linear-attenuate 3-7 mm, commonly persistent into anthesis, then dry deciduous; pedicels at and after full anthesis 6-13(-15) mm, thickened and erect in fruit; fl-buds obovoid, densely pilosulous; sepals submembranous, where covered in bud glabrate and hyaline-margined, nearly isomorphic except the innermost a trifle longer, all oblong or oblong-elliptic obtuse 5-6.5 mm; corolla zygomorphic, the petals bright yellow drying stramineous or whitish brown-veined, thinly pilosulous at claw and along some veins dorsally, all broadly obovate or the 2 abaxial ones narrower and a trifle shorter, the longer ones 11-14 x 5.5-8 mm; androecium glabrous, functionally 7-10-merous, 1-3 adaxial often reduced to linear-spatulate staminodes but sometimes all 10 fertile, the 4 median and 3 abaxial stamens isomorphic except slightly accrescent toward abaxial side of fl, the filaments 2-3 mm, the anthers linear-oblong 3-4 x 0.8-1 mm, slightly incurved thin-textured bicolored, when dry castaneous with broad lateral yellow stripe along the sutures, at apex conical and 1-porose; ovary densely white-pilose; style (1.5-)2-3 x 0.2 mm, incurved from ovary but thence almost straight, not at all dilated distally; ovules 26-34. Pod stiffly erect subsessile oblong-ellipsoid straight (20-)22-32 x 6-7 mm, a little laterally compressed but strongly turgid, abruptly contracted distally into the subulate persistent style-base, the stiffly papery valves early becoming ochra- ceous or dark brown with pale differentiated border parallel to the sutures, densely pilosulous with mixed short fine hairs and coarse setae up to 1.2-2.2 mm, when fully ripe low-corrugate over the seeds, dehiscent downward ± halfway through both sutures, narrowly gaping to emit the seeds but not twisted; seeds closely crowded in 2 interdigitating ranks, each turned edgewise to the valves, in broad profile paddle-shaped (but often distorted by crowding) ±3.8-4.3 x 2.6-3.2 mm, bluntly keeled around periphery, sinuously ridged on broad faces, the testa pale drab- or grayish-olivaceous dull, colliculate and crackled overall, the deeply engraved areole elliptic or subcircular 0.35-0.5 x 0.3-0.4 mm.—Collections: 16.
Distribution and Ecology - Desert flats, washes and stony hills below 400 m, widespread and locally plentiful along the Gulf slope and shore of Baja California and off-shore islands from Isla Angel de la Guarda and Bahia de los Angeles s. to Cabo San Lucas, in lat. 23°-29°30'N.—Fl. primarily I-IV, sporadically throughout the year, prolifically following chubascos, the pods long persisting.
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Discussion
Closely akin to the preceding, which see for differential commentary. Below the Mexican boundary the ranges of S. covesii and S. confinis are almost fully separated by the Gulf of California and they are everywhere morphologically clearcut. On and near Tiburon Island, however, they are either actually sympatric or close neighbors and we have seen one specimen from the southeast side of Isla San Esteban in lat. 28°41'N (Moran 28168, SD) ambiguous between them in characters of the seed. Whether this represents recent hybridization or the undifferentiated stock from which sibling species arose is not determinable.
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Common Names
Oyason
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Distribution
Baja California Mexico North America|