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

130 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN LVOL. 35
because of the usually large and not very markedly asymmetric, marginally rev­
olute leaflets most hkely confused with S. papillosa. In fact we have found no
reliable floral or vegetarive character that will identify these two species at anthesis.
So far as known from fruiring vouchers S. dariensis is actuaUy nowhere
sympatric with S. papillosa, but occupies that disconrinuity in the latter's range
that extends from central Panama east to northwesternmost Colombia and ex­
tends thence, the only species of its sort, south along the Atlantic lowlands to
Esmeraldas, Ecuador. This pattern of dispersal, srill no doubt hable to modificarion
or extension as explorarion of northern Colombia develops, suggests vi­
cariant subspecific differentiation of one primary specific type; but the ripe fruits
of S. papillosa and S. dariensis are so different at maturity, the first cyhndric,
densely papiUate and dehiscent along the ventral suture, the second compressed,
smooth and indehiscent except by rotring or irregular fracture between seeds,
that we cannot seriously entertain the view that only one major species is present.
Schery (1951) seems to have overiooked or underesrimated the carpological char­
acters, subordinaring Chamaefistula dariensis to Cassia oxyphylla and Ch. gatunensis
to C. fruticosa (=our S. bacillaris), an arrangement prompted by undue
emphasis on orientation of the pubescence.
Variarion within 5. dariensis is clearly correlated with dispersal and involves
vesture, length of periole, size of perianth-parts and (simultaneously) width and
compression of the pod, this being at one extreme a very narrow, strongly compressed
ribbon-hke legume containing one row of seeds (as that of S. georgica,
wholly different in the androecium), at the other a broader, compressed-qua­
drangular bean with seeds aligned in two interdigitating ranks. Except that var.
dariensis and var. gatunensis occur together in Darien (e.g. near El Real, cf
Stern 447 and Duke 5093, both MO), the four varieties defined below are fuUy
allopatric.
Key to the Varieties of 5. dariensis
1. Pod 4.5-6.5 mm diam; anthers glabrous or minutely strigulose in the grooves; Costa Rica,
Panama and n.-w. Colombia.
2. Sepals densely gray-puberulent overall, the longest 6-9.5 mm; lfts densely pubescent
dorsally; n.-e. Costa Rica; lowland Panama, from Canal Zone e. into n.-w. Colombia.
3. Lower face of lfts pilosulous with loosely spreading-incurved hairs up to 0.15-0.3
mm; petiole 0.6-1.6(-2.3) cm; sepals persistent under the forming pod.
14a. var. dariensis (p. 130).
3. Lower face of lfts strigulose with forwardly appressed hairs 0.1-0.25 mm; petiole
1.5^ cm; sepals promptly deciduous. 14b. var. gatunensis (p. 131).
2. Sepals glabrous, the longest 4.2-6 mm; lower face of lfts, except for remotely puberulent
major veins, glabrous; cloud forest of Continental Divide in centr. Panama, 300-900 m.
14c. var. hypoglauca (p. 131).
1. Pod 8-12 mm diam; anthers (usually) hispidulous overall with hairs ±0.2 mm; coastal lowland
forest of Ecuador and s.-w. Colombia. Petiole 2^(-5) cm; lfts densely strigulose beneath;
sepals glabrous throughout or beyond middle, the longest 4-8 mm.
14d. var. smaragdina (p. 132).
14a. Senna dariensis (Britton & Rose) Irwin & Barneby var. dariensis. Chamae­
fistula dariensis Britton & Rose, 1930, I.e., sens. str.—"Forest around
Pinogana, southern Darien, Panama, April 1914, Pittier 6579.'"—Holo­
typus, US! clastotypus (fragm), NY!—Cassia oxyphylla var. dariensis
(Britton & Rose) Schery, Ann. Missouri Bot. Gard. 38(1): [=F1. Pan­
ama 5(3)]: 79. 1951.
Chamaefistula boUvarensis Britton & Rose ex Britton & Killip, Ann. N.Y. Acad. Sci. 35: 176
1936.—"Tierra Alta, Rio Sinu, Bolivar [properly Cordoba], Colombia, March 7-10, 1918,
PenneU 4666 . . ."—Holotypus, NY! = NY Neg. 4961\ isotypus, US!