1916] Evans,— Notes on New England Hepaticae — XIII 117 



examined. This can best be done by dissecting off the upper part of 

 the perianth, splitting it, and spreading it out flat, and care must be 

 taken in making sure that the teeth or cilia at the mouth are still 

 intact. The study of old and disintegrated perianths has led to many 

 errors. The teeth or cilia yield characters which can be employed 

 with safety. In P. platyphylla they arc scattered; in P. platyphyl- 

 loidea, densely crowded. It has already been noted that in North 

 American specimens of P. platyphylla the teeth are more numerous 

 than in the European material ; they are never so numerous, however, 

 as in P. platyphylloidea and do not present the appearance of being 

 everywhere close together. 



If neither capsules nor perianths are present the much less satis- 

 factory characters drawn from the habit of the plants and from the 

 leaves are still available. If the specimens to be determined are 

 robust, if the stems are irregularly pinnate, if the lobes of the stem- 

 leaves are as broad as long and distinctly crispate at the base, and 

 if the lobules are about as wide as the underleaves and rounded at the 

 broad apex, there can be little question that the plants should be 

 referred to P. platyphylloidea. If, on the other hand, the specimens 

 are of a medium size, if the stems are regularly bipinnate, if the 

 lobes of the stem-leaves are longer than broad and scarcely or not 

 at all crispate at the base, and if the lobules are distinctly narrower 

 than the underleaves and show a tapering toward the apex, a determi- 

 nation as P. platyphylla is indicated. Unfortunately there are cases 

 where the vegetative characters by themselves can hardly lead to a 

 positive decision. This is true not only of poorly developed specimens 

 but also of well-developed specimens in which the distinctive characters 

 just given are differently grouped; where, for example, an irregularly 

 pinnate stem is associated with narrow lobules or with lobes which are 

 distinctly longer than broad. Male specimens seem to be especially 

 troublesome in this respect and sometimes fail to show the characters 

 of the species clearly when female plants growing with them are typi- 

 cally developed. In the writer's opinion Schiffner's var. subsquarrosa x 

 of P. platyphylla, based on European material, includes forms which 

 cannot be determined positively by means of the vegetative characters 

 alone; and very similar American specimens are listed above under 

 P. platyphylloidea on the basis of perianths and capsules. 



It is evident from the remarks just made that P. platyphylloidea, 



> Lotos 48: 346. 1900. 



