Yucca rigida (Engelmann) TreleaseBlue Yucca, Denticulate-leaf Yucca.
Mo. Bot. Gard. Ann. Rpt. 13: 65-66. 1902.
(The ENGELMANN Herbarium contained 2 specimens (No. s. A. and 477), now lost, of a Yucca collected in 1847 by DR. GREGG, in a dry valley between Mapimi and Guajuquilla, in northern Mexico, which he noted as from 5 to 10 feet high.)
Other representative material studied.fh 0417, Presa Francisco Zarco area 1,240 m
fh 0418, La Fe, 1,450 m
fh 0423, Polsom de Mapimi, 1,160 m
fh 0354 Rio Aguanaval area, 1,550 m
fh 0355, Sierra el Rosario, 1,360 m
fh 0356, Conejos area, 1,240 m
fh 0357, Rio Santa Elena, 1,380 m
fh 0359, La Flor, 1,170 m.
Yucca rigida, fh 0423, Polsom de Mapimi, 1,160m.