126 MINNESOTA BOTANICAL STUDIES. 



The plant from Montevideo is of uncertain relationship. M. 

 Renauld disposes of it by the following suggestions : 



" On the one hand the quadrate alar cells form no distinct 

 auricles, suggesting rather an Amblystegium. On the other 

 hand the form of the leaves is rather that of H. aduncum tenue. 

 The plant being fertile, it ought to be possible to determine the 

 mode of inflorescence. I have not found male flowers, which 

 leads to the suspicion that it is dioicous, and consequently be- 

 longs with Hyfnum aduncum; but inquiry on this point should 

 be made more searching. It is possible that we have to do 

 here with a new species. I commend this plant as well as the 

 one from Ortonville to your attention, since they have in com- 

 mon the square alar cells, which form no auricles, while the 

 general appearance and the form of the leaves are rather as in 

 H. aduncum tenue" 



The plant from Hartford is apparently a more luxuriant form 

 of the same species as that from Montevideo. It has the gen- 

 eral appearance of H.filicinum, agrees fairly in areolation, but 

 lacks paraphyllia. In sending it to M. Renauld I therefore 

 suggested that it looked like a form of H.filicinum. Follow- 

 ing is his comment : " It is easy to be deceived about the rela- 

 tionship of this plant, which is intermediate between H.filicinum 

 and H. aduncum tenue. I am on the whole inclined to see in 

 it rather H.jilicinum. The areolation is very nearly as in this 

 species ; the costa is stronger than it is in H. aduncum, not reach- 

 ing the apex, it is true, but I have observed this in several 

 American forms of Hypnum ftlicinum. I have not found any 

 paraphyllia. But there are radicles, which are not found on 

 H. aduncum. If hybridity in mosses were well demonstrated, 

 I should believe this a hybrid form." 



Dr. Best, who has also seen this plant, considers it to be H. 

 aduncum gracilescens Sch. And the reference of it rather to 

 some variety of H. aduncum than to H. Jilicinum seems, on the 

 whole, to be the more satisfactory disposition. This view ap- 

 pears the more plausible when we consider the richness of forms 

 of H. aduncum in the upper Minnesota, river valley, together 

 with their numerous intergradations. The explanation lies in 

 the evident susceptibility of Hyj>num aduncum to variation 

 under extremes of climatic influences which obtain in that 

 region, especially as regards temperature. 



