MuNz AND JOHNSTON: PLANTS OF CALIFORNIA 43 
’ Penstemon antirrhinoides var. microphyllus (Gray) comb. nov. 
Penstemon microphyllus Gray, Pac. R. R. Rep. 4: 119. 1856. 
Penstemon Plummerae Abrams, Bull. Torrey Club 33: 445. 1906. 
In California this interior form of P. antirrhinoides Benth. is 
known only from the Providence Mountains. Mr. Brandegee 
collected and reported it (Zoe 5: 151. 1903) as P. antirrhinoides, 
while we found it to be rather common on the rocky sides of a 
small canyon back of the Bonanza King Mine. Although quite 
familiar with P. antirrhinoides, as represented on the coastal slopes, 
we could not detect in this desert plant any peculiarities of habit 
or size, though while observing the plant in the field we agreed 
that there was some intangible difference, a difference which was 
later discovered to reside in the grayish hue resulting from a 
cinereous pubescence. 
This shrub was described by Gray from flowerless specimens 
collected by Bigelow on the ‘‘Williams Fork of the Colorado.” 
Based on insufficient material, the plant has remained an obscure 
one: It is not surprising, therefore, that Dr. Abrams, upon 
meeting:so obscure a plant, treated it as though it were unde- 
scribed. It can hardly be doubted that P. Plummerae and P. 
microphyllus are synonyms, for Dr. Gray’s meager description 
applies completely to P. Plummerae, while the types of both are 
from the same phytogeographical area. Significant evidence is — 
found also in the fact that this is the only shrubby Penstemon re- 
vealed by recent collecting in Arizona. 
Dr. Abrams has indicated the characters separating this form 
from the typical P. antirrhinoides, which ranges on the hillsides 
near the coast from San Pedro Martir Mountains northward to 
near San Bernardino, and which is characterized by its very 
broadly ovate sepals and glabrate or puberulent twigs. The 
variety microphyllus, on the other hand, is strictly an interior 
form, ranging from the Providence Mountains eastward into 
western Arizona, and is marked by its distinctly cinereous twigs 
and oblong-ovate or ovate-lanceolate sepals. While the three- 
fold difference residing in the sepals, pubescence and range, argues 
much for specific distinctness of these plants, the relationship is 
so close and so obvious that we feel it best to treat them only 
as well marked geographic forms. 
