LiMPEicHT : Systematic Arrangement of Bog Mosses. 141 



"Russow, " Beitrage," p. 55, joined it with his -S". cuspid atiim 

 Milde, " Bryol. Sil." p. 393, brought it to (S. subsecundum. These 

 different ideas would alone point to the intermediate position which 

 this species takes between 6'. mbsecundimi mrwm and *S^. ciispidatum—' 

 a view which Schliephacke (I.e. p. 27) and other bryologists have 

 repeatedly expressed. Specimens will agree most closely with one or 

 other of these two species according to their habitat : now more with 

 one, and now more with the other species. Apart from the charac- 

 teristic of having two and three layers in the stem-bark, the stem- 

 leaves of this species show good differences. In size and form they 

 are somewhat intermediate between S. subsecundum verum and S. con- 

 iortum, but always possessing in the lower half of the whole breadth 

 of the leaf extremely narrow and very long cells without pores and 

 spiral cells, which become gradually still narrower towards the margin. 

 In this character they remind one of ^\ subsecundum verum and *S'. 

 recurvmn^ but in cell-structure they are far distant from S. subsecundum 

 ,^ isophi/llum. 



All these different forms are comprehended under S. cavifolium, 

 n, sp. Warnst., I.e. p. 79, as a collective species. I suppress any remarks 

 •upon the unjustifiable creation of the new name ; I may, however, 

 just call attention to the fact that one is convinced of the inexpediency 

 of this grouping, even for the seeking out of the species in the 

 annexed two keys at I.e. p. 33-37. 



If before any one, there should be casually placed for determination 

 specimens of S. subsecundum verum, of S. laricinum, or of var. j3 isopTiyl- 

 lum forma a, Russow, with quite similarly shaped branch and stem- 

 leaves, he would hardly, with both keys, guess at the name. ^S*. 

 camfolium. 



For the analytical key-method (for this Pons Asinorum I can feel 

 no enthusiasm) collective species are little adapted ; it is only to 

 species which are based upon one character that it should be applied. 



Sphagnum mriabile, Warnst, I.e. p. 58, is a new name for the well- 

 known S. cuspidatmn, Ehrh., Russow, " Beitrage," p. 55. Older 

 bryologists, such as Sendtner, always looked upon »S'. cuspidatum as a 

 collective species, and they had distinguished already a long series of 

 forms. When C. Muller (1849) proposed his S. laxifolium, he trans- 

 ferred in good faith the name S. cuspidatum, Ehrh., to that plant 

 which we have latterly (following Lindberg) accustomed oui selves to 

 call S. recurmm, P. B. Lately we are invited again to exchange 

 even this name for S. intermedium, Hoff, ; and there are always 

 persons to be found who immediately follow the latest change. 



