;10 ORGANOGRAPHY. 



/ and vessels, as well as parenchymatous cells, are called Vascular 

 J Plants. 



' The lowest orders of Vascular Plants, like the true Mosses, 

 are comparatively insignificant in appearance, such as the Club- 

 mosses {fig. 10); the Horse-tails (fig. 11); and even generally 

 the Perns so far as they are natives of cold and temperate regions 

 (fig. 12), but in the tropics and warmer parts of the globe the 

 latter plants frequently grow to a considerable height, and form 

 handsome trees {fig. 13). These plants, however, like the Mosses 

 and the Thallogens, are all reproduced by Spores, and never pro- 

 duce evident flowers like the higher kinds of plants, hence, such 

 are denominated Flowerless or Cryptogamous Pla?its, that is to 

 say, plants with concealed or invisible reproductive organs. The 

 Cryptogamous plants are again divided into two groups called 

 :iAcrogens and Thallogens ; the latter comprising the simpler 

 I forms of plants, wliich, as previously noticed, are commonly 

 / known as Algae, Fungi, and Lichens, and which present no dis- 

 / tinctionof stem and lea.f {figs. 4 — 7) ; and the former group, those 

 / plants, such as the Mosses {figs. 8 and 9), and the Ferns {figs. 

 * 12 and 13), which present us with an evident stem, bearing leaves. 

 J All plants above the Cryptogamous ones, from possessing evident 

 i flowers or reproductive organs, are termed Phanerogamous, FhiB- 

 nogamous, or Flowering. These latter plants are reproduced by 

 true seeds instead of spores ; a seed being essentially distin- 

 guished from a spore, from containing within itself in a rudi- 

 mentary condition all the essential parts of the future plant in 

 the form of an embryo {fig. 14); while a spore merely consists 

 J-,. of a single cell, or of several 



^3' united, and never exhibits any 



distinction of parts until it begins 

 to develop in the ordinary pro- 

 cess of vegetation, and then only 

 in certain cases. The Phaneroga- 

 mous plants are those, therefore, 

 in which we have the highest and 

 most perfect condition of vegeta- 

 tion, and to these our attention 

 ^The''pe''a!'°? TS^rTdic'i™'''' The ^i^ ^^ more particularly directed 

 axis (tigelle), terminated by the in the following pages. Before 

 sSieaves^ '' *"' *^^ ''''^^^^^^''''^ °'' proceeding, however, to describe 

 in detail the elementary structure 

 of plants and the different parts or organs which they form by 

 their combination, it will be more convenient and intelligible to 

 take a brief review of these compound organs. 



We have just stated that a seed contains an embryo, in which 



khe fundamental organs of the future plant are present in a rudi- 



/mentary state. The embryo of a common pea may be taken 



/for the purpose of illustration {fig. 14). Here we find a distinct 



