608 



BOTANY. 



live examination of the titles compared with the 

 figures, as perfect a knowledge of the system may be 

 acquired, as is necessary for any one seeking informa- 

 tion on the subject. 



For the easy classification of the various tribes of 

 plants, the sexual system as is well calculated as any 

 other artificial scheme that can be devised ; and as a 

 first step to gaining 1 a knowledge of the different 

 forms of flowers it is indispensable. But like all 

 other artificial systems it has its defects ; these are 

 bringing together in the same class, plants which have 

 neither resemblance nor affinity with each other, save 

 in the circumstance of their having the same number 

 of stamens. Some of the true grasses for instance, 

 are classed with genera having no kind of similitude 

 or congeniality ; indeed, many anomalies are found 

 in the system, which show its artificial character, 

 This, as before observed, was felt and acknowledged 

 by the author himself, and has led to the new system 

 of Jussieu, of which we now proceed to give as con- 

 cise an account as is consistent with perspicuity and 

 accuracy. 



The Jussieuian, or Natural System. 



The author of this new system of botany seems to 

 have taken a very comprehensive view of the vege- 

 table kingdom, and has been fortunate in fixing on 

 those greater characteristics of plants which distin- 

 guish them from each other, and which are the most 

 invariable. Looking at vegetable membrane he 

 found it was either uniformly simple, that is, consist- 

 ing of tissues of cells of nearly equal size, or of tissues 

 of which the cells were of various sizes intermixed 

 with each other, and formed into fibres lying in 

 straight or in spiral positions, and forming tubes and 

 openings of different structure and consistence. This 

 evident difference of structure served to divide the 

 whole vegetable kingdom into two parts ; the first 

 he called Cellulares, the second Vasculares. He fur- 

 ther observed, that all the plants of the first division 

 sprung up destitute of seed leaves, (cotyledons) , and 

 those of the second division sprung up from the seed 

 furnished with either one or two seed-leaves. This 

 difference in the germination of the plants called vas- 

 cular, served to separate this grand division into two 

 very distinct classes, namely, DICOTVLEDONE^E, con- 

 taining such plants as rise with two seed-leaves ; and 

 MONOCOTYLEDONS^, those that rise with one. These 

 classes are also very different in the manner of their 

 growth ; the first, Dicotyledonece, is increased annually 

 by additions to the outside, hence called Exogenes; 

 and the second, Monocotyledonece, receives additional 

 matter from the inside, hence denominated Endogenes. 

 Besides these very striking characteristics as regards 

 the growth, the structure and appearance of their 

 foliage is also obviously different. In a leaf of the 

 first class the petiole is extended directly through 

 the web, and as it proceeds, sends off branches 

 towards the margin on both sides, whereas in a leaf 

 of the second class there is no costa or mid -rib, the 

 petiole being divided into several parts, which run in 

 nearly parallel lines from the base to the apex of the 

 leaf. 



By these obvious distinctions in the manner of 

 germination of the seeds, the modes of accretion, and 

 in the structure of the stems and foliage, the two 

 classes of dicotyledoneae are clearly marked. But as 

 there are great differences in the parts and positions 

 of the floral members, the author of the system thought 

 it expedient in order to facilitate the study of it, to 



separate the first class into two subdivisions, and these 

 again into sub-classes, as follow : 



The first grand division, VASCULARES, of which the 

 first class is Dicotyledoneee, rising with two seed leaves. 

 Of this class the first subdivision is Dichlamydece, that 

 is, two coats or coverings, the calyx and corolla being 

 distinct. 



This subdivision is further divided into three sub- 

 classes, viz., first, Thalamiflor(e, containing flowers in 

 which the stamens are seated under the pistillum. 



This sub-class contains fifty-eight orders, all under 

 proper titles derived from some one of the genera, 

 which is assumed as the general type of the order. 

 For instance, the first order is called RanunculacecE, 

 because all the other orders of this sub-class resemble . 

 more or less in structure and form the flowers of the 

 ranunculus, or crowfoot. Here we find associated 

 the anemone, the peony, aconite, columbine, marsh- 

 marigold, hepatica, adonis, &c., all of which show an 

 affinity in their modes of flowering. 



In applying this portion of botanical knowledge, 

 the student has to ascertain whether the seedling 

 rises with two seed-leaves, whether on seeing the 

 flower it presents a calyx and corolla distinct from 

 each other, and finds all the stamens seated below 

 the germen he may conclude that the plant belongs 

 to this sub-class ; and if not to the order Kanuncu- 

 laceae to some other allied order, with the character 

 of which it may better agree in general habit, as to 

 whether herb, shrub, or tree. 



The second sub-class of this division is Calycffloree, 

 containing plants whose flowers have the stamens 

 seated on the calyx. 



This sub-class comprises fifty-eight orders, one 

 thousand one hundred and forty-nine genera, and 

 eleven thousand four hundred and forty-five species. 

 One of the most beautiful orders is the Leguminos<, 

 which contains all plants bearing pods and Having 

 butterfly-shaped flowers. So numerous indeed, and 

 so varied are the genera in this single order that, it 

 is divided into divisions, sub-orders, sub-divisions, 

 tribes, and sub-tribes, in order that the numerous 

 species composing it may be easier understood, and 

 recognised. To the Leguminosce the order Rosacea 

 is the next in importance. Its type, the common 

 rose, is not more regarded for its beauty and scent, 

 than are many of its associates for their excellent fruit. 



Here we find the cherry, plum, apricot, and peach, 

 the principal of our wall fruit of this country ; besides 

 many of our smaller fruit cultivated in gardens, as 

 the gooseberry, currant, strawberry and raspberry. 

 Nor should the fine serviceable fruits, the common 

 apple and pear, be forgotten These also belong to 

 this order ; and for the use of the table, the kitchen, 

 and for the manufacture of cider and perry, are ines- 

 timable. 



The white thorn, with which our fields are divided 

 from each other, and which enlivens with its snow-white 

 blossoms the whole country during the month of May, 

 also belongs to this order. 



Besides the above, many other beautiful flowering 

 plants are also placed here : indeed, all plants bearing 

 rose-like flowers are put into this sub-class, as the 

 myrtle, the Eugenia, trie Barringtonia, together with 

 those useful foreign fruits, the different species of 

 guava. Here also we find the elegant passion- 

 flower, and all those curious tribes of plants from 

 foreign countries, the crassulas, mesembryanthemums, 

 cactuses, cereuses, and the like. Here also is ranked 

 the extensive European family of plants, the saxifrage 



