98 ON THE PHYSIOLOGY OF PLANTS. 



times, by which attention blooming plants may be easily had from 

 April to December. 



Gloxinias are readily increased by inserting the leaves in sand, 

 and placing them in moist peat ; even a leaf laid on the surface of 

 soil in a strong and moist temperature will generally push roots from 

 the ribs of the leaf, and numerous plants be thus produced. 



We suggest the practice of hybridising this with other kinds, and 

 doubt not but some very interesting and valuable acquisitions may 

 be obtained, amply repaying the interesting attention given. 



2. TROP^OLTJM MORTZIANUM. (Mr. Mortis Indian Cress.) 



Tropxolem. Octandria, Monogynia. 



[Tropseolum, from Iropawm, a trophy; in allusion to the leaf and flower.] 



This very interesting species was sent from Cumana to the Glasgow 

 Botanic Garden, and has since bloomed in that and other establish- 

 ments, grown in a conservatory or greenhouse. The stems are 

 twining, growing to about two feet high. It merits a place in every 

 collection. The flowers on the specimen sent us were very interest- 

 ingly beautiful. It appears to be of easy culture, and readily in- 

 creased. When this pretty species is grown in contrast, and after 

 the mode of training practised with T. tricolorum, grandiflorum, 

 elegans, brachyecrus, &c, it will prove a strikingly beautiful object, 

 its fine colours and profuse blooming enhancing its value. 



ARTICLE II. 



ON THE PHYSIOLOGY OF PLANTS. 



BY OI.ITOlt. 



In commencing this subject, I propose to view a plant, naming none 

 in particular, from the time the seed is first placed in the earth until 

 it has attained its full growth, and is enabled to bear seeds of its own, 

 or be propagated by the various principles adopted by gardeners. 



Young plants, when first they have germinated, do not look for 

 nourishment in the earth, being too tender, and not having arrived 

 at that maturity which enables them to seek for themselves, but 

 depend upon the nourishment stored up in the seed. Heat in some 

 degree is necessary for all seeds, in order to render the food required 

 sufficiently fluid for the young plants to take it up. Too much heat, 



