460 PROCEEDINGS OF THE AMERICAN ACADEMY. 



2 to 3.5 mm. broad, submucrouate, narrowed into a subpetiolate base, 

 glabrous or somewhat hirtellous on the upper surface and on the mar- 

 gin, rather densely elongate-punctate : flowers terminating the lateral 

 branches usually in 3-flowered cymes. — Collected about Orizaba by 

 Miiller in 18S5, no. 1523. 



•*- -^ •<- Flowers terminating the stems and branches in small close cymes: 



uncinate bristles of the fruit spreading. 



++ Essentially glabrous : flowers usually white or greenish white. 



8. G-. Seatonii. Perennial : stems prostrate or ascending, much 

 branched, glabrous : leaves sessile, broadly oblong to oblong-lanceolate, 



3 to 10 mm. long, 1.5 to 5 mm. broad, submucronate or short-acuminate, 

 glabrous or slightly hirtellous on the upper surface : corolla about 3 mm. 

 broad, 4-lobed ; lobes oblong-ovate, acute : pedicels later becoming some- 

 what elongated, 3 to 8 mm. in length: fruit 1.5 mm. in breadth. — Mt. 

 Orizaba, altitude 3075 m., 5 August, 1891, Henry E. Seoton, no. 174, 

 distributed as G. uropetalum, Hemsl. ; Federal District, Serrania de 

 Ajusco, altitude 3075 m., G September, 1896, Pringle, no. 6461, dis- 

 tributed as G. Jalapense, Schlecht. 



+* ++ Hirsute-pubescent ; flowers purplish. 



9. G-. Nelsonii. Perennial : stems ascending, 1 to 2 dm. in length, 

 more or less branched, hirsute-pubescent upon the angles and also at the 

 nodes : leaves sessile, ovate or slightly oblong-ovate, acute, usually 

 hirsute-pubescent above and on the midrib beneath, margin ciliate: 

 flowers, bracts, and upper leaves purplish: corolla about 3 mm. in diame- 

 ter, 4-parted ; lobes oblong-ovate, obtusish. — Summit of Mt. Zempoalte- 

 pec, Oaxaca, altitude 3480 m., 9 July, 1894, E. W. Nelson, no. 628. 



* * * * Leaves in fours : inflorescence chiefly axillary. 

 ■1- Flowers on slender pedicels. 

 G. TEXENSE, Gray. Annual, branching from the base: stems more 

 or less erect, 1 to 3 or 4 dm. high, hirsute-pubescent : leaves ovate or 

 oblong-ovate, 0.5 to 1.5 cm. long, one half to two thirds as broad, hirsute- 

 pubescent upon either surface : peduncles axillary, slender, about equal- 

 ling the leaves, occasionally proliferous: fruit 2 mm. in diameter. — 

 Proc. Am. Acad. xix. 80, & Syn. Fl. N. A. i. pt. 2, 36. G. Californi- 

 cum, var. Texanum, Torr. & Gray, Fl. ii. 20. G. uncinidatum, Gray, 

 PI. Lindh. ii. 215? not DC. — Texas, Drummond, no. 115, Lindheimer, 

 no. 619, Wright (without number), on rocky hills near Austin, E. Hall, 

 no. 274, along Brazos River, Palo Pinto Co., Reverchon. No specimens 

 from Mexico, belonging to this species, have been seen by the writer, yet 

 it is altogether probable that the species occurs south of the Rio Grande. 



