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

308 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN [VQL. 35
nodding buds, the axis including peduncle becoming 5-16(-22) cm; bracts resem­
bhng stipules in texture, lance- or ovate-acuminate (3-)4-9.5 x (0.8-)1.2-3 mm,
deciduous as the pedicel elongates; pedicels at and after anthesis 1.4-3(-3.3) cm;
buds subglobose, remotely strigulose-pUosulous or the sepals merely ciUolate;
sepals submembranous pale yeUow commonly fuscous-ringed, oblong-obovate
not much graduated, the outer pah (4-)5.5-8, the inner (5-)6.5-9 mm; petals
yeUow glabrous, broadly oblanceolate or obovate-flabellate, the vexiUary one
often a litrie broader than the rest, the longest 11.5-16 mm; androecium glabrous,
the filaments of 4 median stamens 2-3.5 mm, of 2 latero-abaxial ones (3-)5-8 mm,
of centric abaxial one 2.5-5 mm, the anthers of 4 median stamens 3-5 mm, of 2
latero-abaxial ones (3.5-)4-7 x 1.2-1.7 mm, of the centric abaxial one (3.2-)
3.8-5 X 0.7-1.4 mm; ovary pUosulous; style Unear incurved (0.8-)l-3.5 mm, at
apex 0.2-0.5 mm diam, the stigmaric cavity terminal; ovules (10-)12-28.
Pod obhquely spreading-dechned from ascending pedicel, the stout stipe 5-15
mm, the broadly hnear straight or decurved body 5-11 x 0.9-2 cm, bicarinate by
the stout sutures, the stiffly papery brown valves low-corrugate over the seeds,
the cross-secrion ellipric; seeds either narrowly or broadly, but always plumply
obovoid 4.5-8 x 3^.7 mm, the broadly ellipric-obovate areole 1.7^.8 x 0.8-
1.5 mm.
Along the central and southern Peruvian Andes between Ancash and Lake
Titicaca, around which it extends a short distance into Bohvia, S. versicolor is
the most common and abundant senna of the puna formation, descending only
sporadically on river gravels and rocky quebradas below 2800 meters. Dried
specimens of it are readily recognized by the curious reversed coloration of the
leaflets which, contrary to the common rule in Senna, are brighter or lighter green
above than beneath. In general habit it resembles the sympatric but less common
S. birostris var. huancavensis, which see for comment on differences. Despite
this resemblance, the sharply differentiated areole on the seed faces of 5. versicolor
suggests less affinity with S. birostris than with the four Andean sennas
described next below.
Beyond the range just mentioned S. versicolor reappears locally and, to our
present knowledge, disjunctiy near 7°S latitude in the Maraiion valley in Cajamarca,
and again near latitude 2-3°S in the Andes of Ecuador. The Ecuadorian
plant, of which the pod is still as yet unknown, cannot at present be separated
from common Peruvian S. versicolor, but that from Cajamarca differs abruptly
in number of ovules and «ize of seeds, and cannot be taxonomically ignored. It
is described below as var. heterosperma.
Our concept of S. versicolor differs somewhat from that of our predecessors.
Bentham considered Meyen's plant from Titicaca as the same as Bridges 10 and
Mandon 751, relatively small-flowered sennas here referred respectively to S.
aymara and S. birostris var. controversa, which see for discussion. The excep­
tionally clear photograph of the holotypus, now lost, includes a cleanly laid out
flower from which the petals can be measured at near 15 mm long, altogether too
long for either S. aymara or S. birostris. Furthermore we now have almost exact
topotypes of S. versicolor in the shape of Ugent 5252 (NY) which to our mind
leave no doubt as to the identity of the species, the only senna of its type which
has been collected in the past century on the shores ofthe lake. Thus Bentham's
S. versicolor is a composite without fixed identity. Macbride, on the other hand,
referred (1943, p. 168) C. versicolor and similar material from southeastern Peru
to Cassia hookerana, which he thought perhaps only varietally distinct from C
latopetiolata, supposed to differ (in key) in the less unequal filaments of the