AS AIDS IN THE DETEEMINATION OF SPECIES. (. 



the determination of it is often but a guess at the truth, but this guess can either be 

 verified or proved erroneous, and so advance in this direction will be made. Tliis 

 mode of classification will be the final outcome of all our studies, and to show its 

 superiority we cannot do better than take the fibro-vascular bundle as an example. 



The F.V. B.,* according to the ordinary view, and as the name bundle indicates, 

 is a unity, and treated as such. It is composed of a variety of cells, usually having 

 a definite relation to each other, and either hard and fibrous, or soft and 

 parenchymatous or vascular. 



On the functional view, the F. V. B. is not a unity, but composed of at least two 

 main elements — a part for mechanical support, or skeleton, and another part for 

 circulation. The skeleton and the circulating tissues are often associated, just as the 

 blood vessels have a certain relation to the skeleton in the animal body — the hard 

 and firm to protect and support the soft and yielding parts. 



In describing the sections generally we will adopt a combination of the two latter 

 modes of classification, giving the separate parts, along with their respective 

 functions. Perhaps this might be called, for distinction's sake, the bioniorphic 

 system, as both structure and function are taken into account, and it is undoubtedly 

 the most scientific of all, for the structure did not precede and the use follow, but 

 most probably the necessity for the use arose and the structure was forthcoming. 

 Since life is the cause and not the consequence of organisation, and as life may be 

 regarded as the sum total of the functions, and organisation as the sum total of the 

 structure of the plant or animal body, therefore structure is dependent on — is a 

 manifestation of — function. 



The biomorphic classification of the tissues is based upon the structure, taken in 

 conjunction with the function, the mechanism in connection with its use, and it is 

 added mainly to show the importance of certain structures for purposes of 

 classification. When it is remembered that in a transverse section of even a petiole, 

 we have structures which serve for protection and support, for the manufacture and 

 the transport of food materials, and in fact, for nearly all the vegetative functions of 

 the plant, as distinguished from the reproductive, then such structures become 

 invested with a higher meaning, and with a corresponding classificatory value. 



Adopting a convenient arrangement of parts, which can be seen at a glance in 

 any of the sections, and which will afterwards be further subdivided, they will be as 

 follows from the outside inwards : — 



1. Epidermis or protective tissue. 



2. Cortex, or principally starch-manufacturing tissue. 

 ,3. Hard bast, or supporting tissue. 



Fibro-vascular bundle J 4. Soft bast, or albuminoid-forming tissue. 



is. Wood tissue, or circulatory and supporting tissue. 



* F. v. B. ia used instead of repeating in full the expression, Fibro Vascular Bundle. 



