MULTIPLICATION OF PLANTS. 65 



becoming complete in itself, farms an intimate union with another 

 plant, and lives at the expense of its roots as a sort of parasite. 



8. Propagation by tubercles is another mode of multiplication 

 by division, which is effected by means of buds surrounded by a 

 deposite of nutritive matter, which, being placed in favourable 

 circumstances in regard to moisture, heat, &c., may vegetate and 

 put forth a stem and roots. These deposites of nutritive matter 

 are sometimes formed in the roots, sometimes in subterraneous 

 stems, sometimes in the axil* of the leaves, ordinarily designated 

 under the name of tubercles, off-setts, which, when they have 

 attained a certain size, are usually detached. The potatoe pre- 

 sents us with a remarkable example of this mode of rnultiplica-. 

 tion ; this plant produces along its sterns tubercles which are not 

 developed ordinarily except in its subterraneous part, and are 

 only held by a thin thread, so as to be easily separated at the end 

 of the year, either by the slightest force, or from the death of the 

 stem from which they grow ; now, each one of these tubercles 

 has upon it several buds or germs (called eyes] enveloped by a 

 mass of cellular tissue containing fecula, &c. ; if placed in a 

 situation that is sufficiently moist and warm, these buds soon 

 begin to sprout and attract the nutritive mutters deposited around 

 them ; by means of this nourishment the bud elongates, the stem 

 and leaves begin to develope themselves, and as soon as they 

 begin to perform their ordinary functions, the nutritive juices, 

 prepared within them, descend and cause the formation of roots 

 so as to give rise to a new and complete plant. 



9. To recapitulate : we see, then, that, under certain favour- 

 able circumstances, all plants may be multiplied by division, and 

 that this division may be effected by shoots, by slips, by grafting, 

 and by tubercles ; but in most cases, the reproduction of plants 

 's effected in a manner altogether different, by the means of seeds, 

 which are themselves the production of particular organs : 

 namely, flowers and fruits. 



10. The special organs destined to secure the multiplication of 

 plants are the flowers, fruits, and seeds. 



11. Plants that are provided with perfectly distinct flowers, are 

 designated under the name of Phanerd 'gamous (from the Greek, 

 phaneros, evident, and gamos, marriage) ; and those which have' 

 no distinct special organs of multiplication are called Crypto'- 



* Axil : from the Latin, axilla, arm-pit. The angle or point at which a 

 leaf or branch unites with the stem. 



8. What is meant by the propagation of plants by tubercles ? 



9. How is the reproduction of plants usually effected ? 



10. What are the special organs of reproduction of plants ? 



11. What are phanero'gamous plants ? What are crypto'gamous plants? 



