CHAP. VII 



THE BR \ INE.K 



I8i 



endosporc sometimes grows out in two directions, and one of 

 the papillre remains nearly destitute of chlorophyll and forms 

 the first rhizoid. The growth of the protonemal filaments is 

 strictly apical, no intercalary divisions taking place except those 

 by which lateral branches arise. If abundant moisture is 

 present, the protonema grows with great rapidity and may form 

 a dense branching alga -like growth of considerable extent. 

 Sooner or later upon this arise the leafy gametophores. The 

 development of the latter, as we have seen, also takes place 



Fig. 85. — Funarin hygromcty'ica (Sibth.). A, Fragment of a protonemal branch with a young game- 

 tophoric bud; r, rhizoid; B, median optical section of the bud ; C, older bud — i, surface view; 

 2, optical section ; x, apical cell ; D, protonema with a still older gametophore (^gaiti) attached. 

 A-C, X22s; D, X36. 



abundantly from the secondary protonemal filaments which may 

 be made to grow from almost any part of the gametophore. 



The development of the bud is as follows. From a cell of 

 the protonema a protuberance grows out near the upper end. 

 This is at first not distinguishable from a young protonemal 

 branch, but it very soon becomes somewhat pear-shaped, and 

 instead of elongating and dividing simply by transverse walls, 

 the division walls intersect so as to transform it into a cell mass. 

 After the cell is separated it is usually divided at once by a 



