







ANATOMY, AND LIFE-HISTOBY OF THE CONIFER2E. 



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two, each division extending into a cotyledon. 



In 







In Pinus the general rule is to have twice as many cotyledons as 

 there are vascular bundles in the caulicle, two cotyledons being 

 placed in the intervals between the primary bundles : thus, sup- 

 posing there are five bundles, as in Pinus Pinea, each bundle 

 divides into 



P* canariensis, according to Lestiboudois, has four bundles and 

 eight cotyledons, P. Strobus three bundles and nine cotyledons, 

 P* palustris seven bundles and nine cotyledons, P. maritima five 

 bundles and six to nine cotyledons, P. Laricio four bundles and 

 six cotyledons, or five bundles and six to eight cotyledons, 

 ". calabrica five bundles and eight cotyledons, P. rnonspeliensis 

 four bundles and seven to nine cotyledons, P.j&xcelsa five bundles 

 and twelve cotyledons ; Cedrus four bundles and eleven coty- 

 ledon, the variations in number being due either to subdivision of 

 the bundles, or to the opposite condition of inseparation *. 



i some cases where there are two cotyledons there are, ac- 

 cording to Van Tieghem, two fibro- vascular bundles in the central 

 cylinder of the root, each of which ramifies indefinitely in the 

 aedian plane of the cotyledon, while in the polycotyledonous 

 genera the number of fibro-vascular bundles varies even in dif- 

 ferent individuals of the same species without, however, corre- 

 sponding to the number of the cotyledons t. 



The stomata on the cotyledons vary greatly in number ; they 

 are usually oval, with two-guard cells. As to their position, it 

 is noteworthy that they often occur on the upper surface, or on 

 the lateral faces where the cotyledons are three-sided, even in 

 cases where in the adult leaves they are placed on the lower 

 surface. In many species of Pinus and in Picea Menziesii, where 

 the cotyledons are three-sided, the stomata are almost exclusively 

 on the two lateral surfaces, the dorsal or anterior surface being 

 nearly, if no t quite, destitute of them. The same relative posi- 

 tion of the stomata occurs in the adult leaves of these plants in 

 some Junipers, Picea ajanensis, &c. 



* Lestiboudois in Ann. So. Nat. s6r. 3 (1848), p. 23, t. x. 



t Van Tieghem, < Traite de Botanique ' (1884), p. 1323. For fuller details 

 consult De Bary, * Comparative Anatomy of the Vegetative Organs of 

 Phanerogams and Ferns/ ed. Bower and Scott (1884), pp. 245, 356, 386. 











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ert, ' De seminum germinatione in De Coniferarum Structura Anatouiica ' 

 (1841). Lately Messrs. Van Tieghem and Douliot have shown that in all Gym- 

 ao8perms, as in Angiosperms, the radicels come wholly from the pericycle, and 

 we furnished with a root-cap. 







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