484 PROCEEDINGS OF THE AMERICAN ACADEMY. 



cm. long, 2 to 5 mm. broad, narrowed below into a short petiole, obtusish 

 or acute at the apex, closely appressed-pubescent on either surface, mar- 

 gins revolute: flowers axillary, solitary, scattered along the branches 

 from near the base : calyx-divisions lance-linear, acute, about 3 mm. lonw, 

 slightly unequal: corolla when fully expanded, 8 to 10 mm. broad; tube 

 about equalling the divisions of the calyx ; lobes rounded : nutlets about 

 1 mm. long, slightly hirtellous on the outer upper surface. — Collected by 

 C. G. Pringle on plains near Tehuacau, altitude 1540 m., 29 July, 1897, 

 no. G749. 



Most nearly related to H. Pringlei, Rob., from which it is distin- 

 guished by the more closely appressed pubescence, the less unequal 

 lobes of the calyx, and also by the more rounded lobes of the corolla. 



Heliotropium mexicanum. SufFruticose : stems ascending or 

 erect, 3 dm. or more high, usually much branched, covered below with a 

 brownish pubescent bark, which' gradually peels away from the stem, the 

 stems above and also the branches covered with a rather dense reflexed 

 pubescence, and with scattered ascending stifFer hairs intermixed : leaves 

 alternate, short-petiolate, oblong-oblanceolate to narrowly lanceolate, in- 

 cluding the petiole 1 to 5 cm. long, 2 to 8 mm. broad, the upper surface 

 hirsute-hispid or siib-strigose with shorter finer hairs intermixed, some- 

 what channelled by the sunken midrib and lateral nerves, rather densely 

 and finely pubescent beneath with scattered hirsute hairs intermixed 

 especially upon the raised midrib and arched lateral nerves, obtuse or 

 acute, margin entire, revolute: petioles about 1 mm. long: inflorescence 

 in lateral and terminal usually pedunculate fake racemes, either simple or 

 in pairs, 2 to 20 cm. in length : flowers sessile or short pedicellate, bracte- 

 ate : bracts small, subulate, about 2 mm. long : calyx 3 to 4 mm. long, 

 deeply 5-parted ; divisions somewhat unequal, linear-oblong, obtuse or 

 occasionally acutish, hirsute-pubescent: corolla white, 5 to G mm. long, 

 equally broad when fully expanded, shallowly 5-lobed or pentagonal, 

 somewhat plaited, strigosely pubescent on the outer surface; tube slightly 

 exceeding the calyx-lobes : stamens inserted at the middle of the corolla- 

 tube : nutlets enclosed by the persistent calyx, about 1 mm. long, hirsute- 

 pubescent. — Collected by Prof. A. Duges near Guanajuato in 1880 

 (without number) ; Dr. Edward Palmer, Southwestern Chihuahua, 

 August to November, 1885, nos. 31, 98; Rev. Lucius C. Smith at 

 Cuicatlan, Oaxaca, altitude 554 m., 24 September, 1894, no. 209, and 

 at Las Sedas, altitude 1780 m., 27 June, 1895, no. 391; C. Alvarez, 

 Valley of Elta, Oaxaca, September, 1895 (L. C. Smith's collection), no. 

 750 ; Dr. Edward Palmer on Iron Mountain near the city of Durango. 



