PART I. 

 MORPHOLOGY. 



1. Introductory. An ordinary flowering-plant consists of a 

 number of parts which are distinguished as roots, stems, leaves, 

 fruits, etc. These may be considered scientifically in two ways ; 

 either with reference to their functions in the economy of the 

 plant, when they are regarded as the organs by which these are 

 performed, and are the subjects of physiological study ; or, their 

 functions being disregarded, their relative position, the place and 

 mode of their origin, the course of their growth, and their relative 

 size may be considered ; that is, they may be studied from a purely 

 morphological point of view, when they are regarded merely as 

 parts of a whole, and are designated as members. Hence the pro- 

 vince of morphology is the study of the form of the bod} r of plants, 

 and of the members of which it consists, including the develop- 

 ment of the body and its members, as also the intimate structure 

 (Anatomy and Histology) of the body and its members, in so far as 

 structure throws light upon the morphology of any part of the 

 body. 



The body of a plant, like that of an animal, consists essentially 

 of living substance known as protoplasm. The body may consist 

 only of protoplasm, without any investing membrane to give it a 

 determinate form (e.g. Myxomycetes) ; or it may consist of a mass 

 of protoplasm enclosed by a membrane (e.g. Phycomycetous Fungi 

 and Siphonaceous Algse) ; or it may consist, as in the higher 

 plants, of a mass 6f protoplasm segmented by partition-walls, or 

 septa, into structural units termed cells. In all cases, however, 

 the form and constitution of the body is determined by the proto- 

 plasm ; for the cell-walls of which, in many cases, the body largely 

 consists, and which give to it definiteness of form, are developed 

 from and by the protoplasm. The study of the morphology of 

 plants is, therefore, the study of the processes and products of the 

 formative activity of their protoplasm ; and these are to be traced 



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