OF ARTS AND SCIENCES. 107 
leaves thin, ovate, undivided or more or less hastately 3-lobed, callous- 
denticulate, punctate on both surfaces, glabrous below, minutely pu- 
bescent on the nerves and somewhat scabrous above, 1—2 inches in 
length, acuminate and mucronate at the apex, deeply cordate at the 
base with a rounded open biglandular sinus: glands stipitate, minute, 
4-} line in diameter, on pedicels of equal length: tendrils slender, 
simple: racemes 4-5 lines long: staminate flowers yellow, % line 
broad: rather single, annular, horizontal: fruit } inch long, 4 lines 
broad, very oblique and strongly curved, laterally compressed, acutely 
beaked, armed with a few short weak spines; the convex suture spi- 
rally revolute in dehiscence. — Rocky hills near Patzcuaro, Michoacan, 
October, 1892 (n. 4317). Near C. biglandulifera, Cogn. (ex char.), 
but with more simple tendrils and very much smaller glands. 
PIQUERIA LAXIFLORA. A sparingly pubescent annual, 1} feet 
high: stem weak, furrowed, branching: leaves thin, lanceolate, nar- 
rowed to an obtuse point, serrate, 3-nerved, 14-2 inches long: peti- 
oles 3 lines in length: branches slender, terminating in loose panicles 
with flexuous filiform divisions: bracts minute, linear, 1-1} lines 
long: pedicels filiform, spreading, 3-6 lines in length: heads 4-flow- 
ered: scales of the involucre 4 (2 narrower), thin, green, slightly 
fringed above and mucronate: achenes black, 5-angled, 1 line long, 
narrowed downward. — Cool slopes and ledges, Cafions of mountains 
near Lake Chapala, Jalisco, November, 1892 (n. 4333). Well char- . 
acterized by its very diffuse inflorescence, which suggests Valeriana 
sorbifolia and allies. . 
Piguerta Prinevet. Rhizome horizontal, branching, several 
inches in length: stems subsimple, slender, erect, purplish, 1-1} feet 
high, with a fine grayish pubescence: leaves broadly ovate, an inch in 
length, serrate, rather abrupt at the base, pubescent: petioles 3-4 
lines long : inflorescence a rather dense irregular corymb: heads 2 lines 
long, 4-flowered: scales of the involucre 4, obovate, lacerate above and 
mucronate at the apex: corolla 1} lines long: filaments pubescent : 
achenes glabrous, black, a line in length. — In pine woods, Nevado de 
Toluca, September, 1892 (n. 4285). Habit of P. pilosa, HBK., but 
differing in its well developed rhizome, in its leaves more abrupt at 
the base, and its pubescent filaments. 
STEVIA LAxa, — Root of numerous strong fibres : stem erect from 
a slightly decumbent base, about 2 feet high, purplish, terete, puberu- 
lent, substriate, simple up to the lax finely glandular inflorescence: 
leaves rather numerous below, opposite, ovate, acutish, crenate-serrate, 
1-1} inches long, nearly smooth, paler beneath, contracted below into 
