Coville : The Home of Botrychium plmicola 111 

 Trisetutn subspicatum (L.) Beau v.* 



Carex Breweri Boott. 

 Eriogonum ovalifolium Nutt. 

 Eriogonum pyrolaefolium Hook. 



Eriogonum umbellatum Torr. and another undetermined species. 



Polygonum Newberryi Small. 



Lupinns minimus Dougl. 



Phlox diffusa Benth. 



Phacelia Magellanica (Lam.) Coville. f 



Orthocarpus pilosus Wats. 



Pentstemon Davidsonii Greene. 



Aster Shastensis Gray. 



Hulsea nana Gray. 



Raillardella argentea Gray. 



Hieracium gracile Hook. 



In all these plants there are conspicuous protective modifica- 

 tions which enable the species to endure the summer drouth to 

 which they are subjected. To ordinary circumpolar plants, ac- 

 customed to the more humid conditions of moisture-holding soils, 

 such a drouth would be fatal. The absence of such plants on the 

 deeply cinder-covered summit of Llao Rock may therefore be easily 

 understood. In general the plants of the area are either, like the 

 o n'c/nuw, forms which have been derived from circumpolar 

 generic types and which have developed drouth- resistant charac- 

 is adequate to their survival, or like the species of Eriogonum, 

 e y belong to genera confined to the American continent and 

 growing characteristically at moderate elevations in the arid re- 



* but differ in such a way from these low-elevation species as 

 e a "' e to withstand the severe cold of a subalpine situation. 



■explanation of I»li»te ^ 



dis g " a% entire plant; fig. b, lateral view of frond ; fig. c, base of stem, the sheath 

 c e away so as to show the enclosed bud. Figures a and b are natural size, fig. 

 J W,Ce the ^ural diameter. 



pol 



sn e • / plCal form of the species. It is likely to prove an undescribed species or sub- 



'ess sh l%a AIa S ellan ica is a composite species and a critical study of it will doubt- 



tv pic \1 that the f0rm t0 which the Llao Rock P lant belon g s is not identical with the 



