





232 



DB. M, T. MASTEES ON THE MOHPHOLOOT, 

















the radicle of the Deodar is of a grey colour, that of C. atlantica 

 red. Whether these appearances, observed in a small number 

 of cases only, are invariable, may well be doubted. 



M. Van Tieghem draws attention to the means whereby the 

 radicle of some Conifers (excluding- the Abietineae) is strength- 

 ened and enabled to resist the strains to which it is subjected*. 

 This is effected by the formation of thickenings in the constituent 

 cells of one of the cortical layers next to the endoderm. These 

 thickened cells are peculiar to the root and are not seen in the 

 caulicle \. 



The Caulicle. — The caulicle J is generally erect, slender, of con- 

 siderable length to raise the cotyledons above the surrounding 

 herbage, and of course destitute of branches or rootlets. 



The colour of the bark of the adult tree is often foreshadowed 

 in the colour of the rind of the caulicle. In Cephalotaxus and in 

 some species of Araucaria, as in A. Bidwillii and A. imbricata, 

 the caulicle is carrot-shaped, very thick and fleshy, thus serving 

 as a reservoir of nutriment for the young plant. 



The Cotyledons. — The most noteworthy poiuts with reference 

 to these organs are the hypo- and epigeal conditions respectively. 

 "Where the cotyledons do not appear above ground, or are not 

 much raised above its surface, they are generally thick and fleshy 

 in texture, and do not readily disengage themselves from the 

 seed-coat (see figs. 1, 2, 3). They contain much nutritive matter 

 available for the growing plant. Cotyledons of this character are 

 met with in the tribe Taxese in Cephalotaxus and Grinkgo, and in 

 the section Columbea of the genus Araucaria. The cotyledons of 

 Ginkgo are thick, fleshy, oblong, constricted at the base into short 

 stalks which in germination protrude in an arching direction, 

 leaving the body of the seed enclosed within the shell. The plumule 

















































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* P. Van Tieghem in Ann. Sc. Nat. ser. 7, torn. \ii. p. 374 (1888), " Sur le r6- 

 seau de soutien de l'ecorce de la racine ;" and Ann. Sc. Nat. (1871), t. xiii. p. 187. 



t P. A. Dangeard, in a paper published since this communication was read, 

 and entitled ° La mode d'union de la tige, et de la racine chez les Gynlnospermes, , 

 Comptes Rendus, Feb. 1890, asserts that if there are two cotyledons there are 

 two woody bundles in the root alternating with two liber-bundles; if three 

 cotyledons, the number of bundles corresponds; but if there is a greater number 

 of cotyledons, the number of bundles in the root does not correspond. 



The word " hypocotyl " has of late years been introduced to denote what 

 was formerly called the caulicle or the tigellum ; but as there appears to be no 

 special advantage in departing from the rule of priority, and in adding a 



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synonym to an overburdened terminology, I adhere to the old usage. 









































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