A TKXT-BOOK OF BOTANY. 



nutritive cells of the plant are involved in the process it is some- 

 times spoken of as vegetative multiplication. 



In both lower and higher plants, with the exceptions ju-t 

 noted, reproduction is also carried on by means of spores. 



Fi<.. -. r; ttkrix -.-nata. A, young filament with rhizoid cell (r) ; B, piece of filament 



; <', a swarm spore or zoospore with 4 cilia; D, biciliate 

 jent; E. F, G, showing iliflcrrnt stages of union of two gametes; 



II. :n whirh the i ilia havi- liccn absorl ><.<!; J, i-celled plant 



.nizing zoospores. After Dodel-Port. 



Ik-pending upon their origin two classes of spores are distin- 

 ;iii-hed. namely, (a) a-exnal spores, and (b) sexual spores. In 

 the production of asexual spores the contents of a certain cell 

 railed a mother cell or SPORANGIUM break up into a number of 

 new cell- sometimes called daughter cells, which escape through 

 the crll-wall. Ill the lower plants, particularly those growing 



