CHAMBERS'S INFORMATION FOR THE PEOPLE. 



petals ; and these again were subdivided, according 

 to the position of the stamens with regard to the 

 pistil, in the same manner as the Monocotyledonous 

 plants. To these were added what Jussieu called 

 Diclines, or those plants with separated unisexual 

 flowers. The fault of this system, like that of 

 Linnaeus, was that it associated species dissimilar 

 in their nature; the classification depending on 

 one peculiar feature more than on the general 

 appearance, qualities, and habits of the plant. 



The system of Jussieu was improved by De 

 Candolle, who at first made 161 orders; but these 

 were afterwards greatly increased, and Lindley 

 enumerates upwards of 300. 



The first grand division of De Candolle, like 

 that of Linnaeus, is into the Flowering and Flower- 

 less plants, which he designates respectively the 

 Vasculares and the Cellulares. This division, how- 

 ever, is not absolutely correct ; for although all the 

 flowering-plants contain vascular tissue, and the 

 flowerless consist principally of cellular tissue, yet 

 scalariform or ladder-like vessels are common in 

 the ferns and club-mosses. The Vasculares and 

 Cellulares of De Candolle may be considered as 

 equivalent to the Phanogamia and Cryptogamia 

 of the older botanists. 



His second division depends upon the cotyledons 

 of the embryo; and, like Jussieu, he divides the 

 flowering-plants into DICOTYLEDONES, or those 



with two or more cotyledons or seed-leaves, as a 

 MONOCOTYLEDONES, those which have only one 

 seed-leaf (b, b) ; and ACOTYLEDONES, those having 

 no seed-leaf, and, in fact, no proper seeds such 

 as the Cryptogamia. The differences between 

 these three divisions are decided, and are exhibited 

 in different parts of the plant ; but they are partic- 

 ularly conspicuous in the leaves the venation of 



Dicotyledonous leaves being reticulated, as in the 

 apple (a); and that of Monocotyledonous being 

 chiefly in parallel lines, as shewn in the leaf of the 

 Gloriosa (g). Dicotyledonous trees are said to be 

 Exogenous, from the fact of their trunks increasing 

 by external layers ; Monocotyledonous onzs,Endog- 

 enous, on account of the enlargement taking place 

 from within ; and Acotyledonous trees, Acrogenous, 

 because the increase takes place only at the top or 

 growing-point. 



Dicotyledonous plants are divided into the 

 DichlamydecE, or those with two floral envelopes 



that is, having a separate calyx (a) and corolla (b) ; 

 and the Monocklamydece, or those having only one 



floral envelope, which is always called the calyx, 

 as in the detached floret in the wood-cut (c). 



These distinctions, however, are not always inva- 

 riable, as many plants in the first division have no 

 corolla, but simply a coloured calyx. 



The Dichlamydea are further divided into three 

 sub-classes : I. Tkalamiflorce, in which the sta- 

 mens and petals are all inserted in the receptacle 



Vine: 



a, bunch of flowers ; b, flower before expansion ; c, flower expand- 

 ing; d, stamens and ovary ; e, vertical section of the ovary \ f, 

 fruit ; e, horizontal section of the ovary ; A, vertical section of 

 the fruit, shewing the position of the seed. 



(hypogynous), as represented in the accompanying 

 dissection of the common vine. II. Calyciflorcz, 

 in which the stamens and petals are perigynous, 



Acacia: 

 a, calyx ; 6, corolla ; c, flower ; d, seed-pod open. 



inserted in the calyx, as shewn in the preceding 

 dissection of an Acacia j or epigynous, arising from 

 the upper part of the ovary. III. Corolliflora, in 



