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

226 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN [VOL. 35
proximal and distal pairs of lfts; racemes (5-)7-50-fld, each pedicel subtended
lateraUy by a sripitate or sessUe fusiform gland.—Spp. 4 (perhaps 5, cf. discussion
of S. cana) of tropical e. BrazU (Maranhao and Ceara s. to Rio de Janeiro, w. to
Mato Grosso), 1 extending w. into s.-e. Bolivia and centr. Paraguay and remotely
disjunct in Guyana and Terr. Amazonas, Venezuela.
The two Laxiflorae known to Vogel (1837) formed an element in his Cassia
sect. Prososperma and were carried over by Bentham (1870, 1871) into a some­
what extended section of the same name. The group remains weU characterized
by glands at base ofthe pedicels coincident with a narrow compressed pod crested
lengthwise by a thick accessory nerve; since the discovery of Senna No. 62,
however, vertical orientation ofthe seeds, the signature of Prososperma, is no
longer a common attribute. The Laxiflorae are closely related to ser. Coriaceae
which are simUar in habit and details of androecial structure but different in lack
of accessory nerve on the plane pod-valves and in the insertion of the gland near
or above middle of the pedicel.
The members of this series are closely related to one another and difficult to
separate morphologically in absence of the seldom collected pod. Flowering S.
cana can generally be recognized by the relatively small corolla, and leaflets
either small or numerous compared with the rest; and it has longer-beaked median
anthers. The rest are fully vicariant in dispersal and therefore easily identified if
the source is known.
Key to the Species of ser. Laxiflorae
1. Lfts (2-)3-5(-6) pairs, the blade of distal pairs (4-)4.5-ll cm; gland always present between
proximal pair; fls large, the longer petals 2.5-3.5 cm; beak of 4 median anthers 0.3-0.7 mm,
its channels at apex contiguous but separate; accessory rib on each face of pod displaced
to near middle of valve; range of the series, but scarcely impinging on that of the next.
2. Pod 9-10 mm wide; seeds transverse, with large areole (±3 x 1 mm); style 5-9.5 mm;
n.-e. Brazil (Maranhao to Ceara). - 62. S. lechriosperma (p. 236).
2. Pod 3-5 mm wide; seeds basipetally vertical, with small areole (±1-1.5 x 0.4-0.8 mm);
style 3.5-7 mm; allopatric in Brazil to s. and s.-w., one disjunct in Guyana and s.-w.
Venezuela.
3. Cerrado of Brazilian Planalto w. from R. Sao Francisco, from w. Minas Gerais to
Mato Grosso, centr. Paraguay and s.-e. Bolivia, disjunct in Guyana and Venezuela;
lfts of distal pair mostly oblong-eUiptic or -obovate and (2-)2.2-3 times as long as
wide, commonly but not always pilose on upper face, their secondary camptodrome
veins 10-16(-18) pairs; sepals all pilose dorsally. 60. S. velutina (p. 235).
3. Restinga and coastal shrub-woodland of Atlantic seaboard from s. Bahia to Rio de
Janeiro; lfts of distal pair broadly obovate and 1.3-1.8 times as long as wide, consistently
glabrous on upper face, their secondary camptodrome veins 7-10 pairs; inner
sepals glabrous dorsally. 61. S. australis (p. 232).
1. Lfts 3-8 pairs, the blade of distal pairs 2-6.5 cm; gland nearly always lacking between
proximal though present between succeeding pairs; fls mostly smaller, the longer petals
1.6-2.6 cm; beak of 4 median anthers 0.7-1.6 mm, its twin channels fused to apex; accessory
rib on each face of pod closely approximate to the ventral suture, often narrowly winged;
Bahia to e.-centr. Goias, s. to n.- and w.-centr. Minas Gerais and centr. Espirito Santo.
59. Senna cana (Nees & Martius) Irwin & Barneby, comb. nov. Cassia cana
59. S. cana (p. 226).
Nees & Martius, Nov. Acta Phys.-Med. Acad. Caes. Leopold.-Carol.
12: 34. 1825.—Typus infra sub var. cana indicatur.
Freely branched, densely leafy, potentially or actually arborescent shrubs at
anthesis (1-) 1.5-6 m, with ribbed or obtusangulate atrocastaneous or gray-fuscous
hornorinous branchlets, except for often glabrescent fl-buds and inconspicuously
hairy upper face of lfts vUlosulous or pilosulous throughout with fine incumbent,
flexuous or crisped and entangled, whitish or rufescent hairs up to 0.1-0.5 mm