lis lihodora [AIay 



even if recognized as a \ali(l species, nuist he regarded as a "kleine 

 Art " in the P. plafyiihylla-group. According to our present knowledge 

 the range of the true P. plafi/phylla is northern rather than southern 

 in North America, but it must be admitted that our knowledge is still 

 incomplete. Perhaps when more is known about the geographical 

 distribution of these two species it may be possible to utilize this 

 knowledge in the determination of doubtful specimens. 



Schiffner's Madofhcca Baueri has as yet been reported from Europe 

 only. The writer has not had access to Schiffner's types but has 

 examined a series of authentic specimens including those in Jack, 

 Leiner & Stizenberger's Kryptogamen Badens 164, a^"d in Raben- 

 horst's Hepaticae europaeae 52, both of which are referred by ]\Iiiller 

 to M. Baueri. No. 164 was collected by F. Himmelseher near Salem 

 in Baden and No. 52 by A. Rose near Schnepfental in Thuringia. 

 The specimens studied agree closely with the published descriptions 

 but indicate that the validity of M. Banrri is fully as doubtful as that 

 of M. phityphijlloidea. The characters emphasized by Schiffner are 

 the following: the large size and irregular ))ranching; the broadly 

 elliptical to almost orbicular lol)es; the distant, small, almost plane 

 underleaves, broadly roimded at the apex; the large leaf -cells, averag- 

 ing about 36 /x near the apex of the lolie; the narrow mouth of the 

 perianth with crowded cilia; and the elaters with one spiral, except 

 in the median portion where two are present. Miiller describes the 

 cells in the middle of the lol)e as 30-35 /x in diameter, and adds that 

 one or two blunt teeth are borne on the margin of the lobe, that the 

 lobule is long decurrent and often toothed in the decurrent portion, 

 that the perichaetial bracts are shortly and bluntly denticulate 

 throughout, and that the crowded cilia at the mouth of the perianth 

 are three or four cells long. Aside from the features mentioned 

 M. Baueri is described as being much like P. plafyphylla. 



The material studied by the writer l)rings out the fact that many of 

 the differential characters relied upon are subject to great ^•ariation. 

 This is particidarly true of those drawn from the form and dentation of 

 the leaves. The large leaf -cells afford a character which deserves more 

 weight. The difference in size, when these cells are compared with 

 those of P. plaiyphylla and P. platyphylloidea, is usually pronounced, 

 although INluller brings out the fact that in the variety stihsquarrosa 

 of J/, plafyphylla the cells approach those of M. Baueri. In the mouth 

 of the perianth the resemblance to P. platyphylloidea is particularly 



