16 Contributions from the Gray Herbarium 
found in Rep. Mo. Bot. Gard. xiii. 101-103 (1902). This lucid 
interpretation of an involved nomenclatorial situation will doubt- 
less prove conclusive but the plant to which the name Y. brevifolia 
Schott has been applied must receive a new name because this 
cognomen has been given earlier to another (and valid) species. 
A 845). D. 
Zuce. |. c. 21, nomen nudum; Kunth, Enum. v. 41 (1850). Cordy- 
line longifolia Benth. Pl. Hartw. 53 (1840), not N. longifolia 
Karw.) Hemsley, Biol. Centr. Am. iii. 372 (1884). N. Hart- 
wegiana (Zucc.) Hemsley, |. c. 371. 
Dasylirion longistylum, spec. nov., habitu ignotum; foliis e 
lata basi (6-7 mm. latis) lineari-subulatis 4-5 dm. longis glaucis 
apice fere integris vel breviter fasciculo fibrarum emarcidarum 
terminatis supra plus minusve scabridis margine minute serrulatis 
composita 3-5 dm. longa, spiculis dense multifloris; bracteis e lata 
basi subulatis; e floribus stamineis filamentis breviter exserts; 
capsulis 5 mm. latis, apicibus valde dentatis sed stylo exserto, 
1.5-fere 2 mm. longo; pedicellis 2 mm. longis. — Mexico: San 
Luis Potosi, Minas De San Rafael, 1911, Purpus, no. 5561 (TYPE, 
Gray Herb.). 
The discovery of a species of the Nolineae referable in all diag- 
nostic characters to Dasylirion as that genus is defined by Trelease 
in his tentative revision, Proc. Am. Phil. Soc. 1. 412 (1911) except 
that the pedicels are not “articulated close to the flowers” ut 
rather “ somewhat below the flowers” in the manner of those 
species referred to Beaucarnea, seems to furnish the additional 
evidence needed to prove that Trelease with good reason , 
the question, |. c. 406, “‘ whether Beaucarnea is more than a wel 
marked subgenus of Dasylirion which, strictly limited, itself con 
sists of two quite dissimilar groups.” Unless Dasylirion etait 
mum is removed the only distinctive characters remaining = 
Beaucarnea are the entire perianth segments and the panicled ai 
florescence.. D. longissimum is peculiar in its 4-sided unarmed 
leaves but an occasional slight roughness and low elevations oD the 
leaf-edges suggest the minute serrulations and the spines of a 
Dasylirion. It would not be possible, therefore, except by . 
employment of rydbergianesque methods, to separate D.! 9 : 
simum generically. When the species D. longistylum and D. Os 
simum are both taken into consideration, then, the futihty © 
