452 Rydberg : Rocky Mountain flora 



but with narrower leaves than either. A. piidica Rydb. is re- 

 lated to A. gnaphalodes and A. diversifolia, but in my opinion 

 distinct. This is, of course, a matter of individual opinion. A. 

 Purshiana is a northern plant with much broader leaves and denser 

 inflorescence than the ordinary A. gnaphalodes. It is common 

 in British America and Montana, has been collected in the Da- 

 kotas, and one specimen from Nevada I have referred doubtfully 

 here, but I have seen no specimens from Wyoming or southward. 

 Perhaps this species is unknown to Professor Nelson. 



I must protest, however, against the reduction of Artemisia 

 candicans Rydb., and A.floccosa Rydb. to synonyms of A. gnaph- 

 alodes. Artemisia floccosa, as stated above, should take the place 

 of A . paucicephala and A. gracilenta, and the A. candicans is re- 

 lated to it. Using Nelson's key, one would place it in ^. pauci- 

 cephala, but the heads are still broader, sessile in small clusters, 

 nodding or spreading, instead of erect, and the tomentum is more 

 loose. 



Artemisia Underwoodii Rydb., A. Brittonii Rydb. and A. 

 latiloba (Nutt.) Rydb. are made synonyms of A. ludoviciana 

 Nutt. I doubt if Professor Nelson knew what the first two 

 are. One specimen of A. Underwoodii, Viz., Goodding 1934, 

 was distributed from the University of Wyoming under the 

 name A. silvicola G.E.O. Both A. Underwoodii and A. silvicola 

 are perhaps more closely related to A. mexicana than to A. lu- 

 doviciana. 



Artemisia Brittonii Rydb. has the leaves permanently tomen- 

 tose on both sides and would be placed in A. gnaphalodes if Nelson's 

 key were used. It is most nearly related to A. Purshiana, hut 

 has at least the lower leaves deeply lobed. 



Artemisia latiloba (Nutt.) Rydb. should be known as A. 

 Hookeriana Besser. I have seen a duplicate of the latter in the 

 Gray herbarium and there is no doubt that it is the same as my 

 A. latiloba. It is a northern plant, not found in Wyoming and 

 rare in Montana. It has the same leaf-form as A. elatior and A. 

 Suksdorfii, but the inflorescence is denser and the involucre 

 is densely tomentose. It is sometimes hard to distinguish from, 

 and in the west seem to grade into, what has been known in Cali- 

 fornia and Nevada as A. heterophylla Nutt. The latter name is 



