69 



Groups 1 to 4 include all the principal Stalked Lichens 

 which can be expected in the New \'ork area, with the exception 

 of a v^ery few small and rare ones offering special difficulties. 

 The last species of Cetraria are not exactly stalked, and there 

 are included in the Papery Lichens (Groups 5 to 12) a few 

 species perhaps comparable in form, as already noted. In Group 

 11 are some highly variable forms difficult to classify, and kept 

 together because their algal parts, mostly Nostoc, give them 

 a characteristic water-soaked or gelatinous appearance in shades 

 of black, dark green, dark brown and blue-gray, very different 

 from the greenish gray or yellow tints of most of the larger 

 lichens. 



RiDGEWOOD, N.J. 



An apparent double-sporophyte in Polytrichum commune L. 



Henry N. Andrews, Jr. 



Although the occurrence of abnormalities, such as "double- 

 sporophytes," in the mosses is not common, judging from the 

 accounts of the relatively few students who have concerned 

 themselves with them, one would expect that more careful field 

 examination of large numbers of individuals would bring to 

 light more numerous cases. The relatively inconspicuous nature 

 of the moss habit is probably the chief reason for the few 

 cases on record. 



Gyorffy (1934) and Schimper (1861) have described and il- 

 lustrated double-sporophytes in several genera of mosses includ- 

 ing Orthotrichum , Homalothecium, Anomodon, Bryum, Brachy- 

 thecium, Mnium, and Buxbaumia. In all of these cases the two 

 thecae have a common seta — division of the latter taking place 

 well above its point of union with the gametophyte. The speci- 

 mens described by these authors appear to have been collected 

 when mature and|^fter the calytra had been lost — at least there 

 is no mention of the latter in their accounts. As will be shown 

 below the calyptra may be of considerable significance in de- 

 termining the true ontogenetic morphology of the teratological 

 form in question. 



The two most plausible explanations of this phenomenon are 



