contents. xv 



Section 1. _ 



Page 



THE STE3I OR ASCENDING AXIS . . 69 



1. Internal Structure of the Stem in general . . .70 



A. Exogenous or Dicotyledonous Stem ... 73 



1. Pith or Medulla 75 



2. The Wood 76 



Duramen and Alburnum . . . - 80 



Age of Trees 80 



Size of Trees ' . 82 



Cambium or Cambium-layer . . .83 



MeduUaryKays 83 



The Bark or Cortical System . . .85 



a. The Liber, or Inner Bark, or Endo- 



phloeum 85 



b. The Cellular Envelope, or Green Layer, 



or Mesophloeum . . . .86 

 The Corky Envelope, or Epiphloeum . 86 

 Growth of the Bark . . . .87 



B. Endogenous or Monocotyledonous Stem . . 89 



C. Acrogenous or Acotyledonous Stem . . .96 



2. Buds and Eamification 98 



Buds . 99 



Eamification .102 



1. Non- development of the Regular Buds . . 103 



2. Adventitious Buds 103 



Embryo Buds 104 



3. Accessory Buds . . ' . . . .105 



3. Of the Forms andKinds of Stems and Branches . .106 



Spines or Thorns 109 



Tendril or Cirrhus 110 



Kinds of Stem Ill 



1. Aerial Modifications of the Stem . . .111 



a. The Runner Ill 



b. The Offset 112 



c. The Stolon 112 



d. The Sucker 112 



e. The Rhizome 113 



2. Subterranean Modifications of the Stem . .113 



a. The Creeping Stem . - . . .114 



b. The Tuber 115 



c. The Bulb 116 



d. The Corm 117 



Section 2. 

 the root or descending axis . .119 

 1. True or Primary Root 119 



