6 Contributions from the Gray Herbarium 
eastern United States although it does not replace A. cernuum 
entirely in that section of the country according to Small, Fi. 
S.E.U.S. 2d ed. 263 (1913). No authentic material of A. alleghe- 
niense has been available for examination but specimens from the 
northeastern states of true A. cernuum in the Gray Herbarium 
frequently have the sepals quite as obtuse, and the perianth seem- 
ingly urn-shaped, as is the case with material from the southern 
states. These facts do not suggest, therefore, that A. allegheniense 
is specifically or even varietally distinct from A. cernuwm. 
ALLIUM MUTABILE Michx. This species is the type of a group 
of very closely related plants which seem distinct from each other 
and yet are with difficulty defined so that they may be at all times 
distinguished. For instance there is A. mobilense Regel, All. 
Monog. 121 (1875) which may usually be distinguished from A. 
mutabile by its narrow leaves, shorter perianth and pedicels and 
generally less robust habit and from A. Nuttallii by the softer and 
finer fibres of the outer bulb-coats, the narrower perianth segments 
and the more slender habit. A. mobilense constitutes therefore a 
distinct race or state intermediate between A. mutabile and A. 
Nuttallii and on the whole distinct enough except for a form im 
New Mexico which approaches A. Nuttallii too closely. A. micro- 
scordion Small, Fl. S.E.U.S. 263 (1903) and A. arenicola Small, 
Bull. Torr. Club, xxvii. 276 (1900) are both referable to A. mo- 
bilense. Then there is A. Drummondi Regel, All. Monog. 112 
(1875) which Watson, Proc. Am. Acad. xiv. 227 (1879) referred to 
A. mutabile but which has very different bulb-coats, these being 
firm with the fibres closely woven. A. Helleri Small, Fl. 8.E.US. 
264 (1903) is not to be distinguished. From A. Nuttallii Wats. 
A. Drummondi is least readily separated but the character of the 
bulb-coats here again furnishes the best means of distinction. In 
the southern Rocky Mountains A. Nuttallii, like A. mobilense, 
occurs in very perplexing forms which cannot be placed very Sat- 
isfactorily. It seems possible that the ranges of this group of 
closely related forms, each generally distinct enough, meet in the 
southern Rockies and that there plants occur which display ® 
union of the characters of two or more species. Thus corte” 
Specimens from southern Colorado, Utah and New Mexico while 
possessing some of the characters of A. Nuttallii are referable 2 
other respects to A. mutabile or A. Drummondi or even A. mo- 
