322 PROCEEDINGS OF THE AMERICAN ACADEMY. 



TIT. — NEW DIOSCOREAS FROM MEXICO. 

 ByE. B. Uline. 



Dioscorea pumicicola. Only (^ plant seen. Stem slender, gla- 

 brous, dextrorsely twisted ; leaves cordate at base, deltoid or sub-trilobate, 

 lateral lobes rounded, median part ovate and blunt or abruptly acuminate 

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

 nerves beneath ; flowers arranged iu 3-5-flowered cymules, which are 

 short-pedunculate, and situated at tlie angles of the slender rhachis ; 

 anthers subsessile, triangularly disposed at the centre of the oi)en cam- 

 panulate greenish-brown corolla. 



Leaves 8 to 12 cm. broad, little longer than wide. Petiole 4 or 5 cm. 

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

 dm. long. Cymules 4 to 8 mm. apart, subsessile or on short peduncles. 

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

 whorl shorter. Anthers very minute. — This species is intimately re- 

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

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

 in its lobed leaves and jjubescence. 



Morelos, lava beds near Cuernavaca; C. G. Pringle no. 7227 ^ , 189G. 



D. oaxacensis, Uline in Engl. & Prantl, Nat. Pflanzenf. Nachtr. z. 

 II, 5, p. 8G, without characterization. — Glabrous, glaucous ; leaves 

 chartaceous, cordiform with wide sinus, 9-nerved, exterior nerves on 

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

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

 cicles (rarely solitary), segments of the subrotate G-parted perianth 

 oblong, rather acute, the interior ones slightly narrower ; fertile stamens 

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

 incurved, anthers extrorse in the bud, sterile filaments 3, very short, flat, 

 entire, sometimes bearing effete anthers. 



Stem compressed, angular, sinistrorsely twisted. Leaves scattered 2.5 

 to 4 cm. wide, acuminate. Petioles about 2 cm. long. Racemes as long 

 as 1.5 dm. Floral fascicles 4 to 12 mm. distant, shortly pedunculate. 

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

 membranaceous, unequal, greenish-yellow. 



Syn. D. macrostachya, Mart. & Gal. Bull. Acad. Brux. ix. pt. 2, p. 

 391 (1842), not Benth. 



Mexico near Reyes, altitude 1,800 to 2,050 m., E. W. Nelson, no. 

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



