322 PROCEEDINGS OP Till: AMERICAN ACADEMY. 



m.— NEW DIOSCOREAS FROM MEXICO. 



i;v E. H. I'uxi .. 



Dioscorea pumicicola. Only J plant Been. Stem Blender, gla- 

 brous, dextrorsely twisted ; leaves cordate at base, deltoid or Bub-trilob 

 lateral lobes rounded, mediae p.u-t ovale and blunl or abruptly acuminate 

 at apex, about 7-nerved, glabrous above, Bparsely pubescent on the 

 uerves beneath; flowers arrauged in 8— 5-flowered cy mules, which are 

 short-pedunculate, and Bituated at the angles of the slender rhacl 

 anthers sulisrssilc, triangularly disposed at the centre of the open cam- 

 panulate greenish-brown corolla. 



Leaves 8 to 12 cm. broad, little longer than wide. Petiole 1 or 5 cm. 

 long, puberulent. Rhachis slender, angulate-flexuous, puberulent, 1 to 1.8 

 dm. long. Cymules 1 to * nun. apart, subsessile or on short peduncles. 

 Flowers sessile, 3 mm. wide, with orbicular corolla-lobes, the inner 

 whorl shorter. Anther-; very minute.- This species is intimately re- 

 lated to D. macrostachya and D. spicultfiora, its inflorescence and flowers 

 being essentially the same as the latter, but it differs radically from both 

 in its lobed lea^ es and pubescence. 



Morel os, 1 a a beds near Cuernavaca ; C. < >. Pringle oo. 7227 / . I 



D. oaxacensis, Uline in Engl. & Prautl, Nat. Pflanzenf. Nacbtr. /. 

 II, 5, p. 86, without characterization. — Glabrous, glaucous; leaves 



charta >us, cordiform with wide sinus, 9-nerved, exterior nerves on 



both sides more or less forked; £ racemes elongate, simple; rhachises 

 angulate; flowers shortly pedicellate, in '2 3-flowered rather remote fas- 

 cicles (rarely solitary), segments of the Bubrotate 6-parted perianth 

 oblong, rather acute, the interior ones Blightly narrower; fertile stam< 

 3, subcentral, a little shorter than the segments of the corolla, strongly 

 incurved, anthi rs extrorse in the bud, sterile filaments 3, very .short, flat, 

 entire, sometimes bearing effete anthers. 



Stem compressed, angular, sinistrorsely twisted. Leav< a Bcattered 2.5 

 to 1 cm. wide, acuminate. Petioles about 2 cm. long. Racemes as long 

 as 1.5 dm. Floral fascicles 1 to 12 mm. distant, shortly pedunculate. 

 Flowers 6 mm. wide, on short slender pedicels; corolla-segments thin- 

 membranaceous, unequal, greenish-yellow. 



Syn. D. macrostachya, Man. & Gal. Bull. Acad. Brux. ix. pt. -, p. 

 391 i 1842), not Benth. 



Mexico near Reyes, altitude l.*00 to 2,050 m., E. W. Nelson, no. 

 1786, in part, i. e., as to £ plant, in 1894. The only other specimen 



