ANATOMY OF PLANTS. 19:> 



imperfect plants, propagation is commonly by means ol' buds. 

 The forms and colours still remain in this way, after the pa- 

 rent plant has been completely divided. 



Those plants must be related whose buds are fitted to be 

 propagated together ; but to what extent this relationship 

 must exist is not quite clear. It is certain that evergreens 

 may be propagated on plants which are deciduous, if they be- 

 long to the same genus, (Hopkirk, Flor. Anom. p. 19) * 



It is certain that the usual mode of propagation by layers, 

 grafts, and shoots, diminishes the power of the plants to pro- 

 duce seed. It is hence that Salisburia adiantifolia, Sac- 

 cliarum officinarum^ and Bamhusa aruiidinacea, very seldom 

 produce blossoms or seed with us. 



V. On the Structure of the Leaves. 



C. Bonnet, Recherches sur I'usage des Feuilles dans les Plantee. Geneve, 

 1754. 



308. 



The leaves are an expansion into a surface of those primi- 

 tive forms which in the stem stand near each other, or were 

 inclosed within one another. We hence find the leaves to be 

 altogether of a cellular structure, in those plants whose stem 

 contains no other form, as in the Mosses, among which, how- 

 ever, the Sphagnum ohtusifollum shews the same fine spiral 

 fibres in its cells, which we find on the surface of the stem ; 

 (Tab. III. Fig. 25.) 



• Virgil speaks as a poet, not as a natural historian, when he sings, (Georg. 

 II. 69.) 



Inseritur vero et foetu nucis arbutus horrida, 

 Et steriles platani malos gessere valentes : 

 Castaneae fagus, ornusque incanuit albo 

 Flore pyri ; glandemque sues fregere sub ulmis. 



The best introduction to the artificial propagation of trees is in Munchau- 

 sen's Hausvater, Book V. vid. 675—758. 



N2 



