INTRODUCTORY. 1 1 



degree of morphological differentiation is attained. In the 

 simplest forms, such as the Confervaceae and Ulvaceae, the 

 plant-body consists merely of a filament of cells in the one 

 case and of a flattened expansion in the other. As we ascend 

 we come first to forms, such as Oedogonium, in which, although 

 the plant is a cellular filament, there is a distinction of base and 

 apex ; then to forms such as the Characeae and many of the 

 Florideae in which the body consists of an axis bearing lateral 

 appendages ; finally to forms, such as the Ferns and the Flower- 

 ing Plants, in which the body of the plant consists of parts 

 which stand in definite and constant relation to each other ; 

 these parts are distinguished as stem, leaf, and root, and are 

 termed the members of the plant. 



Having now acquired some elementary general notions of 

 the structure and physiology of plants, we may proceed to the 

 detailed study of each of the functions. Before doing so, 

 however, it will be well to become thoroughly acquainted with 

 the structure of the living plant-cell such as we shall most 

 frequently meet with, as well as with the properties of each of 

 its constituent parts. This, therefore, will form the subject of 

 the next lecture. 



BIBLIOGRAPHY. 



Foster ; Text-Book of Physiology, Introductory Chapter. 



Huxley and Martin ; Elementary Biology, Chapters I and II. 



Rostafinski ; Quelques mots sur Hcematococcus lacustris^ Mdm. de 

 la Soc. Nat. des Sc. Nat. de Cherbourg, 1875 ; also Dyer, Sexual 

 Reproduction of Thallophytes, Q. J. M. S. 1875. 



Strasburger; on Haematococcus in his paper Wirkung des Lichts 

 und der Warme auf Schwarmsporen, Jena. Zeitschr. xn, 1878. 



