98 



THE FERN BULLETIN 



This fern differs from the common polypody P. 



vulgare in the short thin fronds, broadest above the 

 middle, in the pinnules which are noticeably narrowed 

 near the rachis, those below inclining to have rounded 

 or blunt tips but those above ending in long slender 

 points, and especially in the slender pinnule at the apex 

 of the frond. The ferns, though growing in full sun 

 are much more delicate than those of the common 

 polypody which under similar circumstances tend to 

 become almost leathery. The two colonies of the 

 fern discovered were about half a mile apart and were 

 apparently the only species of Poly podium in the vi- 

 cinity. Many of the specimens were forked. 



On the same collecting trip Mr. Ferriss obtained at 

 Weber falls in Weber canyon on the northern side of 

 Mt. Lemmon. a curious form of what is probably best 

 considered a variety of the common polypody. 

 Though growing in rich soil and a fair amount of 

 shade on the banks of a small stream, the largest frond 

 is only four inches long, while the average is under 

 three inches including the stipe. Every frond is 

 heavily fruited and as no larger forms were observed 

 in the vicinity they are probably full grown. Though 

 so small the veins are often twice forked. I would 

 therefore call it Polypodium vulgare var. perpusillum. 

 It may be described as follows: Fronds one to four 

 inches long, one half to three quarters of an inch wide 

 diminishing below, pinnules oblong, obtuse, about 

 eight pairs ; sori medium size, numerous, nearer mar- 

 gin than midrib. Type in the author's herbarium. 



This plant has a superficial resemblance to P. hes- 

 perium but is much narrower and shorter than that 

 form, in fact its diminutive fronds and narrow blades 

 are its most striking characteristics. 



