JONES. — A REVISION OF THE GENUS ZEXMENTA. 159 
San Luis Potost: San José Pass, Pringle, no. 3062. This plant 
seems to have no very close affinities with the other known species, but 
in respect to the achenes it most nearly resembles Z. Pringle. 
+ + Achenes winged. 
++ Squamellae minute or wanting. 
‘ 28. Z. Prineier, Greenman. Tall, slender-branched, suffruticose or 
fruticose, arachnoid-pubescent except on the upper surface of the leaves: 
leaves opposite or the uppermost alternate, ovate, generally less than 3 cm. 
long, subcordate at the base, obtuse or acute at the apex, above rugose 
* and appressed-tuberculate-hispid, beneath densely tomentose ; petioles 4 
to 7 mm. long, narrowly margined: peduncles solitary, long, slender; 
heads 10 to 15 mm. high; involucre 1 to 1.5 cm. broad, about 3-seriate and 
subtended by several leaf-iike bracts ; the inner scales oblong to oblong- 
lanceolate: ligules oblong, about 12 mm. in length, usually half as broad : 
achenes much as in the preceding species but slightly larger and those of 
the ray-flowers verrucose, those of the disk-flowers winged. — 2 Peon Am. 
Acad. xxxiii. 489 (1898).— Southern Mexico. Specimens _— 
Puesva: near Tehuacan, alt. 2166 m., Pringle, no. 6768 ‘neat in herb. 
Gray). 
++ ++ Squamellae evident. 
29. Z. GNAPHALIOIDES, Gray. Slender-branched floccose-lanate 
shrub: leaves deltoid-ovate to cordate-lanceolate, acute at the apex, entire, 
revolute-margined, above shortly sericeous-hispidulous, beneath tomen- 
tose; petioles very short: peduncles long, slender, solitary, tomentose or 
floccose-lanate ; heads and involucre much as in the preceding but the sub- 
tending foliaceous bracts much smaller: achenes short-necked, sparsely 
pubescent, rugose; those of the ray-flowers 3 mm. long, narrow, with 1 
-to 3 fragile awns; those of the disk-flowers with 2 unequal awns and 
narrow wings; squamellae well developed. — Proc. Am. Acad. xv. 36 
(1879). — Central Mexico. Specimens examined, —Sawn Luis Porost: 
between the city and Tampico, Palmer, no. 1106, coll. of 1878-79 (type, 
in herb. Gray). 
Se, 30. Z. Brevirotta, Gray. Fraticose or suffruticose, much-branched, 
a 
bout 1 m. high: leaves ovate or oval, less than 2 cm. long, 1 em. or less in 
width, entire, obtuse at the apex, attenuate to subcordate at the base, 
above strigose, beneath papillose-scabrous, the uppermost alternate : pedun- 
cles long, slender, terminal, solitary, densely strigose ; heads 10 to 15 mm. 
high; involucre lax, about 3-seriate, 1 cm. broad; the outer bracts ovate, 
foliaceous at the apex: ray-flowers 5 to 8; ligules small; disk-corollas 
