Cassiinae pt 1 NY-Botanical_gardens_Vol. 35_1 - Copy.pdf - Antbase

1982] CASSIINAE—SENNA 217
Racemes loosely (subumbellately) 3-10-fld, the axis including peduncle 4.5-14
cm; bracts caducous (litrie known), narrowly lanceolate ±3 mm; pedicels at full
anthesis 24-36 mm; calyx of S. spinescens var. spinescens, the sepals strongly
graduated, the outermost puberulent 4.5-5.5 mm, the innermost glabrate obovate-
suborbicular 11-14 X 9-10 mm; corolla, androecium and pistU of var. spinescens,
the style 1.5-2.5 mm, golden-strigulose almost to tip, there 0.6-0.8 mm diam;
ovules ±34.
Pod unknown.—Collections: 3.
A handsome large-flowered senna, apparently closely related to S. spinescens
var. spinescens and perhaps merely a form or variety of that species, but differing
in the long petiole and few pairs of leaflets, the blades of which are more highly
lustrous and more sharply reticulate-venulose. Collectors describe it as a shrub
or smaU tree, not as a vine, but the specimen may be from young plants in
disturbed igapo woodland. The stipular thorns characteristic of ser. Spinescentes
are present on old wood, but appear less weU developed than those of S. spi­
nescens. The pod is required before the entity can be evaluated.
SPINESCENTES INDETERMINATAE
Buchtien 1778 (NY): Poor specimens, lacking the pod which alone can be deci­
sive, appear to represent a fourth member of ser. Spinescentes. They were collected
at Mapiri, Bohvia at 850 meters elevation, remote both in distance and
environment from the nearest known populations of S. spinescens, and were
described by the collector as hoherer Baum. The flowering branchlets show no
stipular thorns, but these could be present on older stems. The leaves are long-
petiolate as in the unnamed species from Manaus described above, but they are
only three pairs and are accompanied by the glands of ser. Spinescentes. The
calyx is golden-strigulose, much smaller than that of S. spinescens, the outer
sepals ±2.5 mm, the inner only 5 mm long. The petals, while of the same form,
are only ±25 mm long and more shortly clawed. The androecium is that of S.
spinescens except a little smaller.
Bvn. ser. SKINNERANAE Irwin & Barneby
Senna sect. Chamaefistula ser. Skinneranae Irwin & Barneby, stat. et nom. nov.
Phragmocassia Britton & Rose, N. Amer. Fl. 23(4): 245. 1930, pro
gen.—Species unica: Ph. skinneri (Bentham) Britton & Rose = Cassia
skinneri Bentham = Senna skinneri (Bentham) Irwin & Barneby.
Fl essentially that of ser. Laxiflorae and Coriaceae, but style gently incurved
distally, the stigmatic orifice obhquely terminal; ovules 16-24; pod linear piano-
compressed, the sutures undulately constricted between seeds, the valves when
ripe disjointing through the interseminal septa into 1-seeded indehiscent loments;
seeds basipetally descending, subquadrate, turned broadside to the valves; areole
present.—Shrubs, sometimes arborescent, variably rufescent-pUosulous; glands
between proximal and sometimes succeeding pairs of lfts; lfts 3-7 pairs, ample;
racemes mosriy 1-5, rarely -15-fld, the fls large and showy.—Sp. I, of lowland
and submontane s. Mexico, Central America and Venezuela.
Senna skinneri is isolated in the Mexican and Central American floras but has
close resemblance and presumably genetic affinity to the largely Brazilian ser.
Coriaceae and Laxiflorae, from which it differs in lack of pedicellar glands and
in the lomentiform pod. The pod resembles that of ser. Spinescentes, a small