42 



BRITISH CHAROPHYTA. 



and rudimentary branchlets are produced, there are a 

 large number of starch-bearing cells similar to those 

 of -which bulbils are composed. The thickened stem- 



Fio. 15. — Symmetrical star-like stem-bulbils of Nitellopsis oitusa. 

 i. View of upper surface showing pro-embryonic branches and 

 rhizoids originating at the base of metamorphosed branchlets 

 (after Giesenhagen). ii, iii, iv. Various forms of "stars" (ii after 

 H. Groves ; iii, iv after Migula). ( y 7.) 



nodes give rise to numerous rhizoids, and often to 

 accessory pro-embryos and embryonic branches. 



The third type of bulbil, that of a symmetrical 

 star-like form, has been found in Nitellopsis obtusa. 



