YEGETATIVE MULTIPLICATION. 613 



CHAPTER V. 



EEPRODUCTION OF PLANTS. 



Sect. 1. VEGETATIVE MULTIPLICATION. 



It is a remarkable characteristic of the Vegetable Kingdom, 

 shared, indeed, by some of the lower animals, such as Sponges, 

 Polypes, &c., that their organizing forces are diffused throughout 

 their structure, whence results, not only great repetition of simi- 

 lar and, to a certain extent, independent parts in the same plant, 

 but a capability in those parts of surviving when separated from 

 the parent stock, and of becoming the foundations of new plants. 

 Through this condition of the organization arises the possibility 

 of a multiplication of individual plants by simple subdivision of the 

 vegetative structure of a single specimen a process which is not 

 only universal throughout the Vegetable Kingdom, but in many 

 cases is so frequently and abundantly manifested as to throw the 

 proper reproduction by seeds or spores into the background. 



As will be seen hereafter, the spores of some Families are really formed 

 by a kind of vegetative multiplication intermediate between the proper 

 reproductive process and the development of the new plants ; but it will 

 be more convenient to examine those cases in connexion with the forma- 

 tion of spores and seeds generally, and to confine our attention here to 

 what are distinctly and evidently bud-structures. 



Buds ; Gemmae. The modes of vegetative multiplication of plants 

 necessarily depend essentially on the organization of the species ; 

 accordingly as the vegetative structures present more or less com- 

 plexity, so are the " buds " more or less developed at the period 

 when they are detached from the parent. 



Gemmae of Thallogens. In the Thallophyta, where the entire organiza- 

 tion is cellular, and no leaf-structures exist, the buds or gemma are cel- 

 lular structures, more or less complex, according to the condition of the 

 parent thallus. We have examples of the simplest kind of multiplication 

 in Schizomycetes and the lower Algae, such as PalmeUea, Desmidiece, &c., 

 where the plants are continually undergoing propagation by division of 

 the constituent cells. In some cases no other mode of reproduction is yet 

 known, and such multiplication appears to represent the vegetative 

 growth of higher forms ; but in others a true reproduction, with formation 

 of spores, recurs periodically to interrupt the simple cell-division, in a 

 manner analogous to the recurrence of flowering, after a certain extent of 

 vegetative growth, in the higher plants. 



In the Fungi many kinds are abundantly propagated "by conidia, or 

 simple cells detached from the mycelium, as is the case in the growth of 

 Yeast (p. 552), in the propagation of the Vine-fungus, &c. ; and in all pro- 

 bability the Fungi generally may be increased by artificial division of the 



