DIVISIONS OF NATURAL SYSTEM. 99 



By this system all vegetables are divided into two great classes, 

 founded on their structure ; viz., Vascularr.s and Cellulares. The 1st 

 includes the phenogamous, or flowering plants, and the 2d, the crypto- 

 gamous, or flowerless plants. All the 1st are propogated by seeds 

 composed of 1 or more cotyledons and hence are called cotyledonous. 

 while the 2d are supposed to have no seeds, properly speaking, or 

 cotyledons. 



The vasculares possess spiral vessels and a woody fibre, with retic- 

 ulated leaves. The cellulares are distinguished by their cellular 

 structure, having no vascular system, like the first. These classes are 

 characterized further by their structure and growth, as noticed at 

 page 67. 



The cryptogamous, or " flowerless" plants of the Linnean system 

 are included in the d-cotyledonou-s of Jussieu. The monocotyledons 

 consist principally of palms, grasses etc., and are endogenous. This divis- 

 ion consists of 2 large groups : 1st, of plants, the flowers of which 

 have petals, petalloidce, as the lily and iris, the calyx and corolla being 

 in 3 or 6 divisions ; 2d, where the stamens and pistils are surrounded 

 with bracts, glumaca>, as in the grasses. 



The dicotyledons include all the phenogamous plants, or first 23 

 classes of Linnaeus, except the monocotyledons. Those are vascu- 

 lar in their structure or exogenous in their growth. 



The 1st lesson in this system is to examine the seed-lobes, and then 

 to answer the questions 



Has the seed any lobes ? If none, it belongs to Div. 1 ; if it has, 

 then how many has it ? If one, then it belongs to Div. 2 ; and if 2, 

 or more, then it belongs to Div. 3. 



If the seed cannot be found, then the stem or the leaves must an 

 swer the following : Are there any sap and pulp vessels ? If not, 

 then the plant belongs to Div. 1 ; if there are, then is the stem taper- 

 ing upward, covered with bark and the wood softer on the exterior 

 than the interior ? if not, then it belongs to Div. 1 ; but if it is, then 

 it belongs to Div. 3. 



This is simply a notice of Jussieu's method, and there is another of 

 Tournefort's. The 1st depends on the cotyledons, and the 2d on the 

 aspect and other circumstances of the corolla, while the Linnean sys- 

 tem is based on the stamens and pistils. The 1st is thought by some 

 too indefinite; the 2d is not and cannot be relied on, and the 3d is, 

 and has been from the first, the system generally adopted. Jussieu's 

 method, however, is in part, if not entirely, adopted by many distin- 

 guished botanists. 



A few directions may be suggested to those who, from the brief 

 botanical sketch we have given of the artificial system, may desire to 

 make some examinations of flowers. 



An herbarium may be made of a quarto book of white paper in 



