—74— 



fact that in immature condition ail Sphagnum leaves are thus characterized.^ 

 For the mature leaves the feature occurs in some species of all groups of the 

 genus, either as the normal condition of the group or as that of the first phy- 

 logenetic species or rarely perhaps as a tendency of reversion. Furthermore 

 in the lesser number of fibrils in cortical cells and of pores in outer cells of stem, 

 as well as of pseudostomata in the wall of the capsule these species approach 

 more closely those of the other subgenus. My conception of the phylogenetic 

 relations of our species of Inophloea could be expressed by the following diagram: 



Inophloea 



S. papillosum S. erythrocalyx S. magellanicum 



S. palustre 



S. henryense S. imbricatum 

 S. portoricense 



My reason for putting Inophloea before the two sections of Litophloea is the 

 conviction that it is relatively nearer the primitive type of Sphagnum, as shown 

 by its leaf structure without differential margin, the less differenMated branch- 

 cortex, etc. Even the fact that the cortical cells are fibrillose argues for a more 

 primitive condition of things, as these cells are quite analogous to the hyaline 

 cells of the leaves, which are normally fibrillose in all the groups. Warnstorf 

 has reversed this natural order in his treatment in Pflanzenreich without giving 

 any reasons for doing so. He had in Die natiirlichen Pflanzenfamilien (1900) 

 followed an order with which my own is in essential agreement. The rpecies 

 of Inophloea seem also to be relatively older in their separation from each other 

 than those of some of the other groups, notably of the Acutifolia, whose macro- 

 scopic differences, though encouraging in the field, are more truly varietal in 

 their nature. 



Ithaca, N. Y. 



^ Cf. Russow, Zur Anatomic der Torfmoose, 21. Russow's observations (Zur Kenntnis der 

 Subsecundum- und Cymbifoliumgruppe 124) on the chlorophyll cells of the leaves of pi^ndent 

 branches I am unable to confirm, nor do I find otherwise any clear characters of reversion in these 

 branches or their leaves. 



