STANDLEY—TROPICAL AMERICAN PHANEROGAMS. 185 
pubescence of the leaflets. The most striking character, however, which gives 
it an appearance decidedly different from the related species, is found in the 
more or less revolute margins of the leaflets. The pinnae closely resemble 
the fronds of certain species of Polypodium, hence the specific name. 
Acacia leucothrix Standl., sp. nov. 
Unarmed shrub, the branches stout, subtortuous, grayish, densely white- 
hirsute; stipules 2 to 3 mm. long, linear, persistent; petioles 3 to 7 mm. long, 
hirsute, eglandular, the pinnae 3 or 4 pairs, 1 to 1.5 cm. long, the rachis 
densely hirsute; leaflets 9 to 14 pairs, oblong or linear-oblong, 2 to 4 mm. long, 
1 mm. wide or narrower, obliquely rounded at the base, rounded at the apex, 
chartaceous, glabrous, green above, slightly paler beneath, the costa and lateral 
nerves prominulous beneath, the margin plane; flowers glabrous, capitate, 
pedicellate, the heads axillary, solitary, the peduncles 8 to 13 mm. long, hirsute, 
bracteate near the apex; calyx 0.8 mm. long, broadly campanulate, obscurely 
lobate; corolla 3 times as long as the calyx, the lobes oblong, acute; stamens 
very numerous, long-exserted; fruit short-stipttate, flat, 3.5 to 5 cm. long, 6 
to 7 mm. wide, attenuate to the base, rounded to acute at the apex and rostrate, 
glabrous, the valves very thin, prominently reticulate-veined; seeds suborbicu- 
lar, subcompressed, 3 mm. long, olivaceous or grayish. 
Type in the U. 8. National Herbarium, no. 471006, collected at San Dieguito, 
San Luis Potosf, Mexico, June, 1904, by Edward Palmer (no. 148). Also col- 
lected in lowland meadows near Tampico, Tamaulipas, September 3, 1902, by 
C. G. Pringle (no. 9717). 
Closely allied to the plant referred by Small and others to Acacia cuspidata 
Schlecht., but strikingly different in pubescence. 
Acacia laevis Standl., sp. nov. 
Stems slender, terete, purplish brown, glabrous, unarmed; stipules 4 to 5 
mm. long, linear, hirsute-ciliate; petioles 4 to 6 cm. long, without glands; 
pinnae 8 to 11 pairs, the leaflets about 30 pairs, oval or oblong-oval, 3 to 5.5 
mm. long, 1.5 to 2.8 mm. wide, obliquely semicordate at the base, rounded or 
very obtuse at the apex, subcoriaceous, glabrous, green above, the venation 
mostly plane, paler beneath, the venation prominent and laxly reticulate, the 
margin plane, appressed-ciliolate; flowers capitate, pedicellate, the heads partly 
axillary and partly in a long naked raceme, the peduncles 2 to 2.5 cm, long, fas- 
ciculate, glabrous, the bracts small, linear; flowers glabrous, the calyx about 
1 mm. long, companulate, truncate, the corolla 8 mm. long; stamens very numer- 
ous, long-exserted; fruit (immature) about 5.5 cm. long and 8 mm. wide, long- 
stipitate, attenuate to the base, rounded and rostrate at the apex, glabrous, 
glaucescent, the valves very thin. 
Type in the U. S. National Herbarium, no. 296758, collected near Guadala- 
jara, Jalisco, Mexico, July 21, 1902, by C. G. Pringle (no. 11354). 
Closely related to A. tequilana S. Wats., and perhaps only a form of that 
species. In A. tequilana, however, the pinnae are only 8 to 5 pairs, and the leaf- 
lets several times as large and much broader in outline. 
Acacia penicillata Standl., sp. nov. 
Stems slender, terete, purplish and glaucescent, glabrous, unarmed; stipules 
linear, about 4 mm. long; petioles 4.5 to 9 cm. long, glabrous, eglandular, the 
pinnae 8 to 5 pairs; leaflets 15 to 30 pairs, oblong-oval, 6 to 14 mm. long, 3.5 
to 8 mm. wide, obliquely semicordate at the base, broadly rounded at the apex, 
chartaceous, glabrous, dark green or at first glaucescent above, paler beneath, 
the venation prominulous-reticulate, the margin plane, appressed-ciliolate; 
flowers capitate, pedicellate, the heads arranged in a long raceme, the peduncles 
