1916] Evans, — Notes on New England Hepaticae, — XIII 103 



NOTES ON NEW ENGLAND HEPATICAE —XIII. 



Alexander W. Evans. 



{Continued from page 83.) 



In P. platyphylla, according to Miiller anfl other recent writers who 

 define the species in a narrow sense, the secondary stems are more or 

 less regularh- bipinnate or even tripinnate, thus gi\'ing the shoot- 

 system a fern-Uke appearance; the lobes of the leaves are closely im- 

 bricated and ovate when spread out flat, the base being cordate, the 

 apex rounded, and the margin entire or nearly so; the lobules are 

 much smaller than the lobes, about half again as wide as the stem, 

 ovate, gradually narrowed toward the blunt apex, scarcely or not at all 

 deciuTcnt at the base, recurved along the outer side, and entire along 

 the margin; the leaf -cells average 25 ^t in diameter in the middle of 

 the lobe, the cell-walls are thin and the trigones small and triangular; 

 the underleaves are two or three times as broad as the stem and about 

 twice as wide as the lobules, their outline is rotund-quadrate, and they 

 are broadly long-decurrent on both sides, the decurrent portion being 

 sometimes sparingly toothed, while the rest of the margin is narrowly 

 revolute and entire; the perichaetial bracts, which are reduced to a 

 single pair, are smaller than the leaves, and subequally bifid one-half 

 to two-thirds, the lobe being blunt, the lobule pointed, and the mar- 

 gin entire throughout; the perichaetial bracteole is broadly oval, en- 

 tire, and reflexed in the upper part; the perianth is shortly pyriform, 

 bluntly three-keeled in the lower part and florsi-\entrally compressed 

 in the upper part, the mouth being two-lipped and bearing scattered 

 teeth; the capsule is deeply divided into four valves, which are often 

 unequal and further subdivitled; tlie wall of the capsule is two or three 

 cells thick, the cells of the outer wall having small triangular trigones; 

 the spores measure 45-55 yu in fiiameter, and the elaters measure 8 fx 

 in diameter and have two spirals extending to their \ery ends. In the 

 var. subsquarrosa Schiffn., which Miiller admits has been the cause of 

 confusion, the lobes of the lea\"es are broadly ovate, the lobules are 

 broader than in the type but are still narrower than the underleaves, 

 and the cell-walls average about .30 ijl in diameter in the middle of the 

 lobe. 



A study of numerous specimens, both European and North Ameri- 



