RVDBERG : Ro.CKV MOUNTAIN FLORA 687 



description, one can easily see that it without any doubt refers to 

 the true M. canadensis. M. cajiadcusis is not found in the Rock}- 

 Mountain region, and M. glabrior is very rare. The common 

 plant of the Rockies is M. Pcnardi and that of the Pacific slope is 

 M. laiiata, discussed below. 



Mentha lanata (Piper) Rydb. sp. nov. 



Mentha arvensis lanata Piper, Bull. Torrey Club 29: 223. 

 1902. 



Mentha canadensis lanata Piper, Contr. U. S. Nat. Herb. 11 : 

 492. 1906. 



I think that this deserves specific rank, differing not only in 

 the amount but also in the kind of pubescence and in the shape of 

 the calyx lobes. Sometimes the leaves are very densely villous, 

 almost white. Its range extends from British Columbia to Idaho 

 and California. The specimens from Maine accredited to this by 

 Robinson and Fernald * probably represent unusually hairy speci- 

 mens of M. canadensis and not this. 



Mentha occidentalis sp. nov. 



Perennial, with a rootstock ; stem 3—6 dm. high, with short 

 crisp pubescence, at least on the angles above ; petioles 5—10 mm. 

 long ; leaf-blades ovate or ovate-lanceolate, short-acuminate, 

 strongly serrate, 4-8 cm. long, minutely pubescent on both sides 

 or in age glabrate ; bracts linear-lanceolate, i cm. long or more, 

 usually exceeding the flowers ; calyx about 3 mm. long, pilose, 

 teeth lanceolate, acute or acuminate, longer than broad ; corolla 

 white or pink, 5—6 mm. long ; its lobes oblong, obtuse. 



This has been confused with Mentha canadensis and M. gla- 

 brata, but differs from all the species of this group in the long 

 linear-lanceolate bracts, longer than the flower clusters, and the 

 larger corollas. Otherwise it comes nearest M. Penardi. 



Idaho : Forest, Nez Perces County, 1896. A. A. & E. Gertrude 

 Heller j^86 (type, in herb. Columbia Univ.). 



Washington: i?>2>g,Vasey ^6j ; Chehalis River, i?>gj, Lamb 



1235- 



Montana: Jocko River, Aug. 27, 1897, FJrod and assistants 



213- 



* Gray's New Manual 711. 1908. 



