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minutely pubescent clongated or linear-lanceolatt leaves (10 to 17.5 em. long by 8 to 
12 mm. broad), stems 12 to 18 dm. high, and paler flowers, 
+ + + Flowers greenish, yellowish, white, or merely purplish-tinged : leaves opposite or 
whorled, or the upper rarely scattered : pods wholly unarmed. 
++ Pods erect or ascending on the deflexed or decurved fruiting pedicels. 
=Umbel solitary, on a naked terminal peduncle: leaves sessile, broad, transversely veined, 
wary : glabrous and pale or glaucous. 
4. A. obtusifolia Michx. Stem 6 to 9dm. high: leaves oblong with a heart-shaped 
clasping base, very obtuse or retuse: peduncle 7.5 to 30cm. long: corolla pale green- 
ish-purple; hoods truncate, somewhat toothed at the summit, shorter than the 
slender awl-pointed horn.—Dry or sandy soil, extending into Texas from the Atlan- 
tic region. 
= = Umbels usually more than one and on peduncles overtopping or equaling the leaves: 
stem tall and simple: leaves as in no. 4. 
5. A.elata Benth. Glabrous up to the peduncles: umbels 2 to 4 or rarely solitary, 
many-flowered: pedicels pubescent or villous: corolla greenish-white; hoods obo- 
vate-truncate, with fleshy gibbous-ineurved back, the whole length within oceu- 
pied by a broad and thin crest, which is 2-lobed at summit, the outer lobe broad 
and rounded, the inner a short and nearly included horn. (A. glaucescens Gray, not 
H. B. K.).—Extreme southwestern Texas. 
= = = Umbels more than one, on peduncles longer than the orbicular leaves or than 
the much shortened stem. 
6. A. nummularia Torr. Clustered stems 2.5 to 5 cm. high: leaves in two or 
three approximated pairs, orbicular, mucronate, thickish, canescently tomentose, 
glabrate with age: peduncles 3.5 to 4.cm. long, many-flowered: corolla greenish- 
white; hoods ovate, a little longer than the authers, with short and stout horn: pods 
tomentulose.—Extreme southwestern Texas. 
= = = = Umbels mostly more than one: peduncle (sometimes none) not overtopping the 
leaves. 
a. Leaves large, orbicular to oblong-lanceolate: hoods broad, little if at all exceeding the 
anthers. 
7, A. Jamesii Torr. Glabrous or some minute pubescence on young parts: stem 
stout, 3 dm.or more high: leaves about 5 pairs, approximate, remarkably thick, 
rounded or broadly oval, often emarginate, subcordate at base, nearly sessile: umbels 
2 or 3, densely many-flowered, on short peduncles: corolla-lobes ovate, greenish; 
hoods truncate, entire: pod barely acute.—Plains of western Texas. 
8. A. arenaria Torr. Lanuginous-tomentose, glabrate in age: stems about 3 dm. 
high, stout, thickly leaved: leaves coriaceous when old, obovate or oval and retuse 
or the lower ovate, with rounded subcordate base, somewhat undulate, distinctly 
petioled: umbels densely many-flowered, on short peduncles: corolla-lobes oval, 
greenish; hoods truncate at base and summit, the latter notched on each side near 
the inner angle: pod long-acuminate, tomentulose.—Limpia cafion (Nealley). 
b. Leaves narrow, lanceolate to linear, green and nearly glabrous: hoods obtuse, shorter 
than the anthers. 
9. A. brachystephana Engelm. Stems 15 to 25 cm. high, very leafy, cinereous- 
pubcrulent or tomentose when young, the inflorescence more floccose: leaves 2.5 to 
7.5 em. long, much surpassing the 3 to 8 few-flowered umbels: flowers lurid-purplish; 
hoods only half as long as the anthers, strongly angulate-toothed at the front, the 
tip of the erect subulate horn exserted.—Dry sandy soil, western Texas. 
c. Leaves very narrow and slender, sessile: hoods equaling or surpassing the anthers, 
10. A. macrotis Torr. Glabrous or nearly so: filiform branches often 3dm. or 
more long, numerous in diffuse tufts from a woody stem: leaves narrowly linear with 
revolute margins, almost filiform, 2.5 cm. or more long: umbels 3 to 5-flowered, ter- 
