Sphagnales . 7 
most species. In submerged plants the whole stem consists of 
uniform tissue, all the cells except the innermost having chloro- 
Fig. 60. Transverse section of stem of Sphagnum acutifolium. 
Fig. 61. Transverse section of stem of Sphagnum cymbifolium. 
plasts—that is, in such plants the stem-tissue undergoes no dif¬ 
ferentiation and remains in the early stage, which is soon passed 
