102 MISSOURI BOTANICAL GARDEN. 
River (Griffiths, 1909). Pecos Viaduct (Thompson, 1910). 
Marathon (Lloyd, 4, 1910). Sanderson (Thompson, 1911; 
Wooton, 1911). 
So closely allied to Y. Thompsoniana as to be easily con- 
fused with it, is another plant likewise of the group of 
Y. rupicola that differs about as much from the one as it 
does from the other. This may bear a name commemora- 
tive of its collector, the late Mr. Julien Reverchon, an 
enthusiastic student of the flora of northern and middle 
Texas, whose herbarium now constitutes an important unit 
in the large Garden herbarium. 
Yucca Reverchoni Trelease. 
Acaulescent. Leaves narrowly lanceolate, 12-15 mm. 30-40 or 
even 60 cm., nearly flat, straight and rigid, green, at most evanes- 
cently a little glaucous, pungent with a slender at first honey-colored 
spine, the minutely denticulate margin somewhat reddish yellow. 
Inflorescence scarcely 1 m. high, simply paniculate above, at first 
whitened with long soft floccose hairs. Flowers with segments 50-60 
mm. long. Capsules and seeds? 
‘Western Texas, in the region between Y. rupicola and Y. 
Thompsoniana.—Pl. 108. 
Specimens examined:—San Angelo (Reverchon, 4030, 
May 20, 1903,—the type). Near Ft. Clark (Havard, 18, 
October, 1883). Comstock (T’hompson, April 12, 1911). 
Accumulated material shows that each species of the 
rupicola alliance may be expected to occur in a form entirely 
lacking the normally characteristic marginal denticulation 
of the leaves. At present such smooth-edged forms are 
known for three of the five species, and for distinction they 
may be named Y. rupicola edentata (Cedar Hill, Dallas Co., 
Texas, Reverchon, 968, June 20, 1903), ¥.rostrata integra 
(Hacienda de la Babia, near Sabinas, Coahuila, Mex., End- 
lich, 1161, March 10, 1906*), and Y¥. rigida inermis 
(Symon, Zacatecas, Mex., Sra. de Chivo, June, 1908, re- 
ceived from Professor F. E. Lloyd with the local name 
Palma San Jose, under his number 77). 
* Cf. Rept. Mo. Bot. Gard. 18. 226. 
