CONTRIBUTIONS FROM THE GRAY HERBARIUM OF HARVARD 
UNIVERSITY, NEW SERIES, No. XXXI. 
Presented by B. L. Robinson, April 12, 1905. Received June 6, 19065. 
I. DESCRIPTIONS OF SPERMATOPHYTES FROM THE 
SOUTHWESTERN UNITED STATES, MEXICO, 
AND CENTRAL AMERICA. 
By J. M. GREENMAN. 
TRADESCANTIA FLUMINENSIS, Vell. Fl. Flum. 140, t. 152 (1790); 
C. G. Clarke in DC. Monogr. iii..294. Specimens of this white-flowered 
South American species were secured by Sefior Professor A. Duges in 
the vicinity of Guanajuato, Mexico, 1904, no.3 (hb, Gr.). According to 
Professor Dugés the plant is not cultivated there, but is found growing 
wild in moist shady places about the city of Guanajuato, although it is 
rare. The species does not seem to have been recorded hitherto irom 
Mexico. 
Hymenocallis riparia, n. sp. Leaves lorate, 2 to 6 dm. long, 7 to 
14 mm. broad, entire, bordered with a narrow whitish subcartilaginous 
margin, glabrous, their bases expanded, persistent and forming a mem- 
branous collar 10 to 12 cm. in length: peduncle 3 to 3.5 dm. long, flat- 
tened: spathe-valves 2, lance-attenuate, 3.5 to 6 em. long, thin and 
scarious: flowers 3 to 7, sessile: perianth white ; tube of the perianth 8 
to 12 em. in length; divisions of the perianth nearly or quite equalling 
the length of the tube, 3 to 5 mm. in breadth, 5-7-nerved : staminal cup 
broad-funnelform, 2 to 2.5 em. high, subentire ; free portion of the fila- 
ments 5 to 6 cm. long, slightly broadened at the base, gradually tapering 
to the 1.5 em. long verticillate anther, greenish: style much elongated, 
greenish ; stigma overtopping the anthers: ovary sessile, bearing 3 to 7 
ovules in each cell, these ascending from the lower inner angle of the 
cell and sometimes subsuperposed. — Mexico. State of Morelos: by 
streams near Cuernavaca, 11 November, 1895, C. @. Pringle, no. 5979 
(hb. Gr.), and in the same locality, 27 July, 1896 C. G. Pringle, no. 
7204 (hb. Gr.) ; rocky river banks, barranca of Cuernavaca, altitude 
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