336 BOTANICAL GAZETTE [OCTOBER 
to this species. A more intimate acquaintance with the Salix flora 
of these regions may lead me to a different opinion, but I hesitate 
to refer any doubtful forms to a certain species as long as I do not 
yet know all the other willows that may occur in the locality. 
Different species may sometimes look very similar at a certain 
stage of their development, and it needs a long time and the most 
scrupulous observation to become familiar with the variation of 
such polymorphic plants as the willows usually are. 
4. S. BRACHYCARPA Nutt., North Am. Sylva 1:69. 1843; 
RypBERG, Fl. Colorado, 95. 1906; Fl. Rocky Mts. 197. 1917; 
BALL in Coult. and Nelson, New Man. R. Mt. Bot. 135. 1909.— 
S. desertorum Andersson in DC. Prodr. 167:281. 1868, saltem var. 
8 et y, non Richardson; Bess apud RorHRock in Wheeler, Rep. 
U.S. Geog. Surv. west rooth Merid. 6: Bot. 241. 1878; in Coulter, 
Man. Bot. R. Mts. 338. 1885, excl. var.; BALL in Trans. Acad. Sci. 
St. Louis 9:85. 1899, pro parte.—S. stricta Rydbg. in Bull. N.Y. 
Bot. Gard. 1:273. 1899; in Mem. N.Y. Bot. Gard. 1:114 (Cat. Fl. 
Mont.). 1900.—The type of this graceful and well marked species 
was collected by Nurra.t in August 1818 “‘in the Rocky Mountain 
range, on the borders of the Bear River, a clear rapid brook cutting 
its way through basaltic dykes to the curious lake of Timpanagos, 
in New Mexico”’ (now the Great Salt Lake of Utah). No type 
specimen seems to be in existence, neither have I seen a plant from 
the type locality, but NuTraLt’s ample and vivid description leaves 
no doubt as to the form of which he is speaking. ANDERSSON 
entirely misunderstood this species when (in 1867 and 1868) he 
added NutTaLt’s name with ? as a synonym to his S. longi- 
folia argyrophylla angustissima. Rowtee (in Bull. Torr. Bot. 
Club 27:248. 1900) seems to have been the first who reinstated 
Nvttatt’s name for S. stricla (And.) Rydbg. As already stated, 
S. brachycarpa is apparently connected with S. pseudolapponum 
by intermediate forms, and in 1899, through his investigation of 
the Rocky Mountain material, BALL was led “to the conclusion 
that no rigid line can be drawn between the species as they 
are represented in that region.”” The extreme forms, he said, are 
widely divergent, but the numerous intermediates present an 
almost perfect gradation between these extremes. After all, this 
