September 30, 1909 ll<J 



taken on August 2d. So far it has been detected on Mt. R 

 nil the granite formation only. 



The genus Pentstemon, with the exception of one species 

 said to occur in northeastern Asia, is American, and confined 

 chiefly to the region west of the Mississippi river. About two 

 hundred and forty named forms have been recognized as occur- 

 ring- north of Mexico, and of this large number only thirty-nine 

 according to the Cyclopedia of American Horticulture, have 

 been introduced into cultivation. 



Practically all of the species have showy flowers ranging in 

 color from white to violet-blue, deep rose color and scarlet, and 

 also exhibit quite a variety of structure, some of them having 

 a long, almost cylindrical tube and short lobes, while others 

 are more or less funnel-form with broad spreading lobes, and 

 one small group has the narrow upper lip merely emarginate, 

 the lower one pendulous and recurved. There is also great di- 

 versity in the make-up of the throat of the corolla, in some in- 

 stances that part being channeled or pleated and partly closed, 

 while again it may be open and unobstructed 



The flowers have five stamens, hence the name of the 

 genus, as opposed to the four stamens of related genera, but the 

 fifth one is normally sterile. It is commonly spatulate in shape 

 at the apex, and this is either naked or densely bearded on the 

 lower side. In some species the fertile stamens are also bearded. 

 The fertile stamens are unequal, two of them longer than the 

 other two. The short ones are inserted at the base of the lower 

 lip but free from it while the long ones are affixed to the tube 

 for its whole length. The sterile filament is adnate to the up- 

 per lobe up to a point a little above the tube, when it abruptly 

 curves inward. The characters concerning the stamen insertion 

 are generic, at least for the species with more or less inflated 

 corollas, and should be given a place in the generic description, 

 but so far I have not found them mentioned in any of our floras. 



The species of Pentstemon are mostly herbaceous peren- 

 nials, but a few of them are decidedly woody at bast.', and sex- 

 era! Californian ones, notably the crimson flowered P. tordifol- 

 ius. have long vine-like branches. 



