Studies on the Rocky Mountain flora — XXIV 
PER AXEL RYDBERG 
- Saussurea densa (Hook.) Rydb. sp. nov. 
Saussurea alpina densa Hook. FI. Bor.-Am. 1: 303. . 1833. 
Saussurea alpina Ledebouri A. Gray, Syn. Fl. 1?: 397. 1884. 
Not S. Ledebourt Herder, 1810. 
Saussurea Ledebouri Herder was based on S. subsinuata, 
S. nuda, and S. Tilesti of Ledebour, which Herder united into one 
species under another name. All three are illustrated in Lede- 
bour’s Icones Fl. Ross., and it is evident that S. alpina densa 
Hook. is different from each of them. None of the three illus- 
trations shows the elongated, acuminate outer bracts, character- 
istic of S. densa. Only S. nuda shows a dense inflorescence with 
subsessile heads and a low stem, but the heads are fewer and less 
crowded, the stem is naked above, and the leaves entire. 
S. densa is a plant of the higher mountains of the Canadian 
Rockies. 
“ Saussurea remotiflora (Hook.) Rydb. sp. nov. 
Saussurea alpina remotiflora Hook. Fl. Bor.-Am. 1: 303. 1833. 
Saussurea alpina A. Gray, Syn. Fl. 12: 396, in part. 1884. 
Saussurea nuda Britt. & Rydb. Bull. N. Y. Bot. Gard. 2: 187. 
1901. Not. S. nuda Ledeb. 1829. 
This species is nearer to Saussurea subsinuata Ledeb. than to 
either S. alpina or S. nuda, but the inflorescence is laxer and the 
involucre is different, judging from Ledebour’s illustration.  S. 
remotiflora grows on low ground from northern Saskatchewan to 
Yukon and Alaska. 
CaRDUUS 
So many species of thistles have lately been described from 
the Rocky Mountains that the number has more than doubled 
since the issue of Gray’s Synoptical Flora. Some of these species 
should be reduced to synonymy and some of them are probably 
hybrids, but I think that the larger number will remain as good 
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