464 PROCEEDINGS OF THE AMERICAN ACADEMY. 



* * * Leaves elliptic to oblong-ovate, usually 3-nerved from the base, bearing a 

 single large gland or cluster of glands on tlie lower surface at the tip. 

 H- Leaves distinctly 3-nerved, margins strongly revolute. 



16. Gr. hypadenium, Schauer. Suffrutesceut : stems prostrate 

 or ascending, glabrescent, often leafless and little branched below, cov- 

 ered with a thin grayish bark which later separates from the stem, freely 

 branching above ; branches tetragonal, pilose-hirsute : leaves sessile, 4 

 to 10 mm. or more long, nearly one half as broad, obtuse, usually hirsute- 

 pubescent, more or less glabrate above, rather densely white-pilose or 

 merely hirsute beneath, margins ciliate : corolla 4-parted, about 2 mm. 

 in diameter ; lobes externally pubescent with rather long hairs : fruit 

 about 2 mm. in breadth ; carpels somewhat separated at maturity. — 

 Linnaea, xx. 700. G. lencotrichum, Hemsley, Biol. Cent.- Am. Bot. ii. 

 65, & V. t. xli. figg. 4-6. — Orizaba, Milller, nos. 174, 1218, Sumichrast, 

 no. 514; Puebla, dry limestone ledges near Tehuacan, altitude 1540 m., 

 27 August, 1897, Pringle, no. 6694; Guerrero, between Chilopa and 

 Tixtla, altitude 1540 to 2150 m., 17 December, 1894, E. W. JS^elson, 

 no. 2166 ; Jalisco, near Guadalajara, Pringh, 5046. 



17. G. fascum, Mart. & Gal. Perennial: stems tetragonal, be- 

 coming more or less scabrous along the slightly thickened angles, the 

 yoitnger stems and branches bearing scattered pilose-hirtellous slightly 

 curved hairs: leaves elliptic-oblong, 0.5 to 1.5 cm. long, 2 to 8 mm. 

 broad, short-petiolate, submucronate or merely acute, glabrous or spar- 

 ingly hirsute above and upon the nerves beneath, conspicuously glandular- 

 punctate ; margins usually ciliate : inflorescence cymose-paniculate : 

 flowers brownish purple ; lobes of corolla commonly pubescent. — Bull. 

 Acad. Brux. xi. i. 126; AValp. Rep. vi. 13; Hemsley, Biol. Cent.-Am. 

 Bot. ii. 64. — Oaxaca, Cerro de San Felipe, Gnleotti, no. 2633, dry hills 

 near the City of Oaxaca, altitude 1845 m., Pringh, no. 4795 (distributed 

 as G. uncinulatum, DC., var. abstipum, Watson), near Re3'es, altitude 

 1750 to 2000 m., E. W. Nelson, no. 1774 ; Guanajuato, Dug^s. 



I- -1- Leaves indistinctly 3-nerved, margins little or not at all revolute. 



18. G-. hystricocarpnm. Stems usually many from a perennial 

 base, ascending, more or less branched above, covered with a spreading 

 pilose-hirsute pubescence : leaves elliptic-oblong to oblong-lanceolate, 

 5 to 12 mm. long, 2 to 7 mm. broad, short-acuminate or submucronate, 

 hirsute on the upper surface and upon the midrib and inconspicuous 

 lateral nerves beneath : flowers white, somewhat cymose-paniculate or 

 terminating the lateral branches in few-flowered cymes : lobes of the 

 corolla covered externally with a few long pilose hairs. — Cool cliffs and 



