10 CLASSIFICATION OF PLANTS. 



rous species which constitute our bulbous flowers have all ribbon-like leaves, 

 differing in little except hi length and breadth ; and their floral envelopes, 

 though splendid in point of colour, are generally more simple than those of 

 exogens, being often of one piece or of one series of pieces ; and there is also 

 very little variety in their fruit. Compared with acrogens, however, 

 endogens are still high in the scale. 



26. To be able to refer any plant that may be met with to the class to 

 which it belongs, is already a grand and useful step in the progress of bota- 

 nical knowledge ; and in the practice both of botanising and of vegetable 

 culture, it is of more real use than a knowledge of the whole system of 

 Linnaeus. The moment one botanist or gardener tells another that a plant 

 is an exogen, he forms a perfect idea of its structure, and even some 

 idea of its culture; because the leaves of exogens are more numerous 

 than those of endogens, and hence, with the exception of the grasses, 

 they suffer less from transplanting and mutilation. The leaves of 

 endogens, on the other hand, as of all the bulbous plants, are compara- 

 tively few, and therefore all of them require to be preserved unin- 

 jured. If they are cut off, either in their growing state or when fully 

 formed, they are not renewed the same season ; and the bulb not being 

 nourished by them, will not flower the following year. Exogens, on the 

 other hand, may have their leaves cut off without much injury, especially 

 in the early part of the season, as they have an indefinite power of renewing 

 them, and consequently, what would render an endogen floweiiess the fol- 

 lowing year, would have little or no effect on an exogen. Grasses, however, 

 are an order of endogens which possess the same properties of renewing their 

 foliage as exogens, and hence a grassy surface may be cropped by cattle, or 

 mown with the scythe all the summer, and yet live and thrive. But sup- 

 pose a lawn composed of plants of hyacinth, tulip, narcissus, or crocus, the 

 leaves of which are not unlike those of the grasses, to be mown when the 

 leaves were fully grown, in that case the plants would not produce another 

 leaf that season, and instead of a green lawn we should have the naked earth 

 till the following spring. 



27. These three grand classes of plants are divided into orders and tribes, 

 genera, species, and varieties. The orders of plants indigenous or cultivated, 

 in Britain, amount to upwards of 200, and the tribes to perhaps a third of 

 that amount. The genera amount to upwards of 3,700, and the species to 

 up wards of 30,700. (Loud. Hort. Brit.) The varieties of botanists are perhaps 

 1,000 ; and those of culinary vegetables, fruits, roses, and florists' flowers, may 

 amountt o perhaps 10,000. Now, though it is not to be expected that any 

 individual can know, and bear in his mind the names of one-tenth of 

 these plants, yet it is extremely desirable that he should be able to speak of 

 any one of them, when he meets with it, whether it has been previously 

 seen by him or not. For example, a very slight degree of attention to a 

 plant seen for the first time, will enable any one to determine to which of 

 the three grand divisions it belongs. Next, in each grand division there are 

 two or three of what may be called popular orders, which orders any person 

 may recognise almost at sight ; and to these orders belong fully half the 

 plants which are commonly met with in Britain, either in a cultivated or a 

 wild state. A knowledge of the grand divisions of these popular orders, 

 therefore, will be a grand step gained, and give the gardener or amateur a 

 notion of a great number of plants. The grand divisions of Exogens are 

 Thalamifloree, Calyciflorse, Corollaeflorae, and Monochlamydeae. 



