26 PROCEEDINGS OF THE AMERICAN ACADEMY. 
++ Petioles glabrous. 
++ Leaves pilose on the nerves beneath. 
A. arguta, Spacu. Bark of the branches and branchlets brown, 
glabrous: buds short-stalked, glabrous: leaves ovate or obovate, acute 
or bluntish, rounded or somewhat narrowed at base, finely but sharply 
double-serrate, 0.4 to 1 dm. long, 3 to 7.5 em. broad, sparingly glandular- 
dotted, but glabrate above, paler beneath and pilose especially along the 
nerves; petiole slender, 1 to 2.5 cm. long: peduncles slender, glabrate ; 
staminate aments 4 to 7 in terminal panicles (becoming about 1 dm, 
long): the dark reddish-brown strobiles 3 or 4, sessile, sub-cylindric, 
when mature 2 to 8 cm. long, about 1 cm. thick: the cuneate obovate 
or oblong nutlet 2.5 cm. long, 1.5 mm. broad, somewhat broader than 
the coriaceous wing. — Ann. Sci. Nat. ser. 2, xv. 205. A. acuminata, 
a genuina, Hemsl. Biol. Cent.-Am: Bot. iii. 165, not Regel. A. jor- 
ullensis, var. castaneaefolia, Hemsl. 1. c. 166, not Regel. Betula arguta, 
Schlecht. Linnaea, vii. 139.— Vera Cruz, Mt. Orizaba, April 10, 
1867 (Bilimek, no. 404), without date (Botteri, no. 857) ; alt. 3400 m, _ 
Aug., 1891 (H. #. Seaton, no. 231). Originally described from VERA 
Cruz and TaMAULipas. 
_ ++ ++ Leaves glabrous, or at most only slightly pubescent when young. 
A. glabrata, n. sp. Bark of the branches brown, glabrous: buds 
short-stalked, sparingly puberulent or glabrous: leaves oblong-lanceolate 
or elliptic, long-acuminate, narrowed or slightly rounded at base, coarsely 
and doubly serrate-dentate especially above, paler and dull beneath, the 
yellowish or brownish nerves prominent; petiole to 1 to 3.5 cm. long : 
peduncles thickish, glutinous ; staminate aments 3 or 4, becoming 7 or 8 
cm. long; the dark brown or blackish strobiles oblong or cylindric, ses- 
sile or short-stalked, in maturity 1.8 to 2.8 em. long, 9.5 to 14 mm. thick : 
nutlets oblong to oblong-lanceolate, 3 to 5 mm. long, 1.5 to 2 mm. broad, 
_ with slightly narrower coriaceous wings. — A. acuminata, Sargent, |. ¢, 
in part, not HBK.— Guanasvato, Mt. San Nicholas, April, 1882, 
and Santa Rosa, April, 1901 (4. Dugés): QuerETaro, between Mexico 
and Queretaro, November, 1827 (Berlandier, no. 1294): H1pa.eo, 
Dublan, December 4, 1902 (C. G. Pringle, no. 11,179); Mexico, Val- 
ley of Mexico, June 1, 1865-66 (Bouryeau, no. 244), Dec. 9, 1892 
(C. G. Pringle, no, 4361); near Tizapan, alt. 2300 m., Jan, 30, 1899 
(C. G. Pringle, no. 8022): Oaxaca, Valley of Oaxaca, alt. 1570 to 
thats Sept. 8, 1804 (Z. W. Nelson, no. 1254); near Huajuapam, 
t. 1725 to 2000 m., Nov. 16, 1894 (&. W. Nelson, no. 1976); Coyula 
iar 
a pei «15 
ses Men S At Ta Se ht ee TS The Ed 
LO Set ES LS etc ke ag ta ee ey ae 
