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

154 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN [VOL. 35
of pedicel, either early caducous or persisting into anthesis; pedicels at and after
anthesis (10-)12-32 mm; buds globose but the sepals separated before true an­
thesis by the expansion of petals and androecium; sepals firm subherbaceous,
usuaUy densely, often subvelurinously gray-strigulose externally and puberulent
within (rarely glabrate), not much graduated, all convexly ovate, oblong-ovate or
suborbicular, always obtuse, the longest (4-)4.5-6.5(-7.5), very exceptionally
-9 mm, externaUy nerveless or fainriy 3-nerved; petals firm, biscuit- or darker
orange-yeUow, pubescent externaUy and at least near base also within, subhomomorphic
except the adaxial one somerimes broader, oblong-obovate or oblan­
ceolate beyond the short claw, (9-)10-15(-17) mm, heavUy 3-veined from claw,
the veins externally prominent; androecium funcrionaUy 7-merous, the filaments
puberulent, those of 4 median stamens 0.8-1.8(-2.5) mm, those of 3 abaxial ones
(1.5-)2-3.5(-5) mm; anthers glabrous or more commonly either puberulent along
the grooves or minutely pilosulous overall, those of 4 median stamens (4-)4.5-9
mm, truncate, with very short 2-porose beak standing at right-angles to the little-
incurved body, those of 3 abaxial ones shorter, 3-5.5 mm, with beak hardly longer
(-0.9 mm) but slighriy more porrect; ovary densely silky-pUosulous or -strigulose,
at anthesis incurved over androecium, the more thinly pubescent or glabrate
style 2-4 mm, abrupriy swoUen at apex into a cobra-like head 0.9-2.8(-3) mm
diam, the obhque cup-shaped stigmatic cavity 0.6-1.8 mm diam; ovules
(112-)122-196(-220).
Pod pendulous short-stipitate, the stipe 2-A mm, the narrowly subcylindric
nearly straight body 11-33.5 x 0.9-2 cm, the firm, coarsely transverse-venulose
valves turning brown or fawn-color, dehiscent along ventral suture to expose the
seeds clothed in fetid black pulp; seeds (not weU known) biseriate, turned broad­
side to the septa, broadly oblong or oblong-obovoid compressed, the testa smooth
lustrous brown, sometimes broadly but faintly areolate.
Senna quinquangulata is the commonest and most frequently collected of that
group of Bacillares collectively characterized by lustrous, marginally revolute
leaflets, a gland between each (rarely between only the proximal) pair of leaflets,
a thyrsoid-paniculate inflorescence arranged around a straight primary axis, and
a pod lacking thickened margins to the sutures. In the lower Amazon valley,
interior Guayana, the middle Orinoco basin and parts of northern Venezuela and
Panama its range overlaps that ofthe related S. undulata, or perhaps more exactly
interfingers with it, for the latter is apparently adapted in equatorial latitudes to
more porous sandy soils supporting a savanna cUmax vegetation and extends
northward beyond S. quinquangulata onto the karst limestones of Yucatan. In
any case within their common range S. undulata is instantly recognized at an­
thesis by the enlarged floral bracts and little dilated style. The largely West Indian
S. viminea and wholly West Indian S. nitida are fully allopatric, the first differing
in its short pod and the latter in the loss of one or two of the abaxial set of
stamens. The sometimes deceptively simUar S. oxyphylla has a gland between
the lower pair of leaflets only.
As here delimited and as already, at least in some degree, known to Bentham,
S. quinquangulata is variable in orientation, density and length of pubescence
and in amplitude of the petals, although these only exceptionally and locaUy (e.g.
Bahia, Harley et al. 17516, NY) surpass 15 mm in length. In middle Amazonia,
especiaUy around Manaus, it is represented by a race with the relatively small,
strongly undulate leaflets of S. undulata, here considered taxonomically unim­
portant, and independently on upper Rio Branco in Terr. Roraima and in southern
Mexico by forms with densely pilosulous upper branchlets and inflorescence.