GENERAL MORPHOLOGY. 



otliers branched in Tarious ways {fig. 33). In these simple plants 

 we are unable to distinguish any separation of the nutritive and 

 reproductive functions, which is so evident in the higher plants, 

 but_the cell of which they are composed is capable of performing 

 both these functions. The plants immediately above these con- 

 sist of numerous cells combined in a single row, and either 

 simple (fig. 4), or branched in a variety of ways (figs. 5 and 6). 

 In these plants we frequently find one or more of the cells ac- 

 quiring a special development, and producing in their interior a 

 number of others of a smaller size (fig. 4). Here we have the 

 first trace of a separation or distinction of the cells of a plant 

 into_tli0se adapted for nutrition, and 

 those for reproduction, as the smaller 

 cells thus developed in fhe Interior of 

 tlie larger ones are especialTy designed 

 for reproducing the plant, in the same 

 manner as the seeds of Flowering 

 Plants are adapted for that purpose. 

 These reproductive particles are termed 

 spores or sporvdes {fig. 4). 



In the plants above these we find 

 the cells combined in various ways, so 

 as to form flattened leaf-like expan- 

 sions {fig. 7), or solid axes, as well 

 as special organs of reproduction {fig. 

 7, t). 



Up to this point, however, although 

 we have, as just noticed, certain cells 

 containing reproductive particles, yet 

 we have no examples of plants present- 

 ing any distinct axis bearing leaves. 

 Such plants are therefore called Thallo- \ 

 gens ^^JThMojphytes, that is plants 



C!aasistingofa7tfl7k5,because the latter ^^.^y ^^.^^^^ „f ^^^ ^„„ 

 term is appKed to any cellular filamen- 

 tous or flattened leafy expansions, of 

 whatever form, which have no axis or 

 stem distinct from a leaf, but the two combined as it were 

 together, and performing the ofl&ce of both. Under the head of 

 Thallogens we comprise those simpler forms of plants which are 

 commonly known as Algae, Fungi, and Lichens. 



By various intermediate stages through an order of plants 

 called the Liverworts, we arrive at a series of plants, viz. the true 

 Mosses {figs. 8 and 9), which present us with an evident stem, 

 hearing leaves. In these also we find the first trace of roots, in 

 the form of little tubular prolongations composed of cells pro- 

 ceeding from the lower part of the stem. In the Mosses, there- 

 fore, we^have first distinctly shadowed forth the three essential 



in on Bladder Sea-weed (Fucus 

 vesiculosiis). t. The fructifica- 

 tion. V, V. Bladders of air. 



