THE HIGHER CRYPTOGAMIA. 139 



that the branch developes a number of lateral branches 

 before the commencement of the formation of leaves ; and 

 he treats the scale-like appendages of the young branch- 

 buds, which I considered to be leaves, as being the rudi- 

 ments of lateral branches (PI. XVII, fig. 6). Continued 

 observations have not afforded me a single phenomenon 

 confirmatory of this opinion of Schimper's. I have found, 

 without exception, that the lateral branches develope indis- 

 putable leaves at a very early period, almost close to their 

 place of insertion into the principal stem (PL XVII, fig. 1), 

 and I have never seen a branch of the second order inserted 

 on a primary branch underneath the place of origin of the 

 first leaf. The points at which the axile cellular strings 

 are separated from the branches,, often appear to be enclosed 

 within the bark of the fully developed principal shoot (1. c, 

 pi. iv, fig. 4) ; but this appearance is caused by the com- 

 paratively late commencement of the growth of this bark in 

 the direction of its thickness ; the bark is closely attached 

 to, and grows round, the base of the branches, and strips 

 off" their lowest leaves. 



I found that the development of the stem and branches 

 of Orthotrichum affiue agrees in all essential particulars with 

 that of Sphagnum. 



The first division of the rudimentary leaf-cell, which pro- 

 trudes slightly above the circumference of the terminal bud, 

 takes place by means of a septum springing laterally from 

 its longitudinal axis, and perpendicular to the surfaces of 

 the leaf. This division is succeeded by that of the apical 

 cell, which takes place by means of a septum inclined in 

 the opposite direction, meeting the one previously formed 

 at an angle of 90° (PL XVII, fig. 3). By the repeated 

 division of the apical cell by means of alternately inclined 

 septa, the leaf grows in length. During this time the form 

 of the apical cell is that of a low, three-sided prism, and the 

 form of the cells of the second degree is that of a procum- 

 bent parallelopiped. 



Contemporaneously with or very shortly after the forma- 

 tion of a new cell of the second degree, the next older one 

 divides by a transverse septum, which, like all those which 

 take part in the formation of the leaf of Sphagnum, is per- 



