184 rHYTOTOMY. 



stalk, from the sap-vessels and spiral-vessels, formed by the 

 compressed cellular texture. The solid fundamental body 

 pushes towards the side, horizontally, the young shoot, which, 

 being nourished by its parent substance, is not separated from 

 it until it also has acquired a firm fundamental body, crowned 

 with scales, and is able, consequently, to maintain itself. 



Between this lateral impulse and the upright one, which 

 produces the stalk, there is such an interchange, that the one 

 of these impulses languishes when the other is most active. 

 Hence it is usual, after the flowering of bulbs, to lay them 

 dry, that the quiet lateral impulse may remain undisturbed. 

 Bulbs, which have once completely blossomed and produced 

 seed, usually die. 



III. On the Structure of the Stem. 



H. Colta, Naturbeobachtungen uber Bewegung unci Function des Saftes in 

 den Gewachsen. Weimar, 1806, 4to. 



J. Chr. F. Meyer, Naturgetreue Darstellung der Entwickelung, Ausbildung 

 und des Wachsthums der Pflanzen. Leipsig, 1808, 8vo. 



C. Pollini, Saggio di Osservazioni e di Sperienze sulla Vegetazione degli 

 Alberi. Veron. 1815, 8vo. 



H. L. du Hamel de Monceau, La physique des arbres. A Paris, 1758, 4to, 

 Vol. I. 2. 



P. Keith, System of Physiological Botany, Vol. I. p. 284 — 362. 



290. 



The internal structure of the stem varies according to the 

 great divisions of the vegetable kingdom, which we have no- 

 ticed above, (171. and Part II. Chap. 6.) 



In plants the seed of which contains an undeveloped and 

 rich albuminous body, the bundles of woody fibres, consisting 

 of sap-vessels and spiral- vessels, are spread through the whole 

 stem, and are every where divided by cellular texture. This 

 is most distinctly perceived in the trunks of Palms, in tlie 

 3tems of the Scitamineoe, Musca?, Orchidese, and Coronarise, 

 This dispersed situation proceeds from these plants having no 



