690 Rvdberg : Rocky Mountain flora 



casus A. Gray. A careful reading of the original short description 

 of Gray's variety will reveal to anyone that it cannot apply to P. 

 Xylus. As P. suffrutescens was based exclusively on Gray's variety, 

 it can by no means be called a nomen nudum as Professor Nelson 

 is inclined to regard it. To it I refer also P. procumbens Greene 

 published nearly two months later. 



Pentstemon Thompsoniae (A. Gray) Rydb. sp. nov. 

 Pentstemon pumilus Thompsoniae A. Gray, Syn. Fl. 2 1 : 269. 



1878. 



This is a very distinct species, not related to P. pumilus. Dr. 

 Gray at first * placed Pentstemon pumilus with P. albidus, P.Jamesii, 

 and P. cristatus, i. e., in a group to which it rightly belongs, not- 

 withstanding its small size. Afterwards,! he transferred it wrongly 

 to the P. caespitosus group, with which it has little in common. 

 P. Thompsoniae on the contrary belongs to this group and is a 

 close relative to P. caespitosus. I suspect that Dr. Gray has 

 redescribed the true P. pumilus Nutt. under the name P. miser. X 

 I have not seen the type of the latter but the description agrees 

 well with P. pumilus. 



Pentstemon platyphyllus sp. nov. 



Pentstemon heteropliyllns latifolius S. Wats. Bot. King's Exp. 

 222. 1 87 1. Not P. latifolius Hoffm gg. 1824. 



Dr. Gray in the Synoptical Flora § refers this doubtfully to 

 Pentstemon azureus J affray anus Gray (P. /affray anus Hook.). The 

 two resemble each other in leaf form and general habit, but there are 

 differences important enough to make them distinct species. I am 

 also, inclined to think that P. Jaffrayanus is specifically distinct 

 from P. azureus, although I have not seen any authentic specimen 

 of the latter. The leaves in P. Jaffrayanus are strongly glaucous 

 and the upper are subcordate and clasping at the base ; the calyx- 

 lobes are oval or obovate, abruptly short-acuminate or mucronate 

 with an erect tip ; the anthers are somewhat hirsutulous at the 

 sinus as well as papillose-hispidulous on the margins ; and the sterile 



*Proc. Am. Acad. 6: 67. 1862. 

 fSyn. Fl. 2 1 : 269. 1878. 

 % Syn. Fl. ed. 2, 2 1 : 441. 1886. 

 \ 7} : 272. 1878. 



