450 CONSERVATIVE ORGANS. [t,ECT. IX. 



pagated by slips or buds, never become so com- 

 pletely naturalized as to bear all the variations 

 of the new climate with impunity; but plants 

 which are propagated by seeds, although natives 

 of very warm climates, yet, become perfectly na- 

 turalized to colder in a certain number of genera- 

 tions. 



Botanists enumerate three kinds of sponta- 

 neously separating Hybernacula, the Propago, 

 the Gongylus, and the Bulb; and one which does 

 not spontaneously separate from the parent, the 

 Gem. 



The PROPAGO * is thus denned by Gaertner : 

 " A simple leafless, polymorphous, or variously 

 " shaped germ, in some instances naked, in others 

 " enclosed in a cortical sheath^ which sponta- 

 " neously separates from the parent, and is scat- 

 " tered in the manner of seed." It is a small 

 pulpy or cellular body of no regular shape ; and 

 is sometimes covered with an epidermis. It is 

 readily found in dividing the tubercles and 

 shields or saucerlike bodies, which appear on the 

 surfaces of Lichens, in an early stage of their 



* This term was used by the ancients chiefly to denote a 

 cutting of the Vine, when buried in the ground to throw up 

 new shoots ; but it was applied also to cuttings of other plants. 

 Arbores aut semine proveniunt, aut plantata radice, aut propa- 

 gine, aut avulsione, aut surculo, aut insito et consecto arboris 

 trunco. Pliny, 1. 17. c. 10. 



