18 PRIMARY DIVISIONS OP THE VEGETABLE KINGDOM. 



6G. These Grand Divisions are further distinguished by their 

 organic structure and general aspects. In the Phsenogamia we find a 

 system of compound organs, such as root, stem, leaf, bud, flower, suc- 

 cessively developed on a determinate plan ; while in the Cryptogamia, 

 A gradual departure from this plan commences, and they become, at 

 length, in their lowest forms, simple expansions of a uniform tissue, 

 without symmetry or proportion. This distinction is rendered perfectly 

 clear by a reference to 



G7. Examples. Compare a rose with a fern. In tho former a regular axia 

 bears buds which arc unfolded, some into leaves, others into flowers succeeded by 

 fruit. In the fern no buds nor flowers appear, and the fruit dots sprinkle over the 

 back of the leaf. Again, contrast the violet with a lichen, where neither stem, root, 

 nor leaf appears, much less flowers, but disc-liko expansions with fruit-dust (spores) 

 produced indifferently in any part of them. 



68. Subdivisions of the Phsenogamia. This grand division is 

 itself very naturally resolved into two subdivisions, named by Dc CandoUe 

 Exogcns and Endogcns. 



09. Exogenous plants or Exogens (outsidc-growers), including all 

 the trees (except palms) and most herbaceous plants of temperate regions, 

 arc so named, because the additions to the diameter of the stem are 

 made externally to the wood already formed. 



70. Endogenous plants orEndogens (inside-growers), includingthe 

 grasses and most bulbous plants of temperate climates, and the palms, 

 canes, etc., south, arc so named from the accretions of the stem taking 

 place within the parts already formed. 



71. These subdivisions are more accurately distinguished by the 

 structure of the seed. The seeds of the Exogens consists of two equal 

 seed-lobes, called cotyledons, as seen in the pea. The seed of the Endo- 

 gcns consists of but one seed-lobe or cotyledon, as in the Indian Corn. 

 On this account Exogens were first called Dicotyledonous (two-cotyle- 

 doned) plants, and Endogcns, Monocotylcdonous (one-cotylcdoncd) 

 plants ; — names quite appropriate, but too hard and long for general use. 



72. They are also very readily distinguished by their leaves, 

 which are net-veined in the Exogens, and parallel-veined in the Endogcns. 

 Moreover, their flowers arc remarkably different, being almost always 

 three-parted in the latter and about five-parted in the former. But all 

 these distinctions, with some others,will bo more definitely stated hereafter. 



73. Tiie Name of a plant or other natural object is twofold, — tho trivial or 

 popular name, by which it is generally known in tho country ; and the Latin name, 

 by which it is accurately designated in scieneo throughout tho world. For example, ' 

 strawberry is the popular name, and Fragaria vesca tho Latin or scientific name of 

 the same plant. 



74. In elementary treatises, like the present, for tho sako of being readily under- 

 stood, plants arc usually called by their popular names. Yet wo earnestly recom- 

 mend to tho learner to accustom himself early to tho use of tho more accurate names 

 employed iu science. 



