TABLE OF CONTENTS 



FIRST SECTION. 

 GENERAL DIFFERENTIATION OF THE PLANT-BODY. 



PAGE 



I. INTRODUCTION. MORPHOLOGY AND ORGANOGRAPHY .... 3-13 



Definition of Morphology 3 



Relation to Physiology .......... 4 



Views of Metamorphosis ......... 5 



Transformations and arrest 6 



Metamorphosis as a change of function 6 



II. DIFFERENTIATION OF ORGANS IN THE SPERMAPHYTA .... 13-21 



Inefficiency of definitions based only on characters of form . . 13 



Form is only one superficial and inconstant character ... 13 

 Definition of organs must be based upon all their characters and 



their function must not be overlooked 14 



Homologous and analogous organs ....... 14 



Homologous organs are not always of common genetic origin . 17 



Polyphyletic divergent development from simple primary forms . . 19 



Descendant forms with like developmental capacity .... 19 



III. FORMATION OF ORGANS AND DIVISION OF LABOUR AMONGST THE 



LOWER PLANTS (THALLOPHYTA) 21-40 



Many paths to higher differentiation from simple beginnings . . 22 



Differentiation of root and shoot only a special case ... 22 



Unicellular and pluricellular plants 22 



Monergic and polyergic cells 23 



Cell-colonies and cell-dominions ........ 24 



I. Colonies or coenobia ......... 25-32 



A. Colonies which are not fixed 25 



1. Colonies of naked energids 25 



2. Colonies of energids invested by a membrane . . 26 



a. Protococcaceae ....... 26 



b. Volvocineae 27 



