CONTENTS Xiii 



PAGE 



Series B. The Differentiated Dicotyledons . . .645 

 Orders 13-24. Ranales to Umbellales .... 646 



Series C. The Specialized Dicotyledons .... 653 

 Orders 25-32. Ericales to Campanulales : . . 653 



CHAPTER XIV. THE ECOLOGICAL CLASSIFICATION OF PLANTS . 558 



1. The Ecological Groups 558 



2. Plant Habitats and Vegetation Forms . . . . 659 



(1) The Water Habitats and the Hydrophytes . . . 561 



(2) The Aerial Habitats and the Aerophy tes . . 664 



A. The Optimum Habitats and the Mesophytes . . 566 



B. The Humid-Dry Habitats and the Tropophytes . 667 



C. The Dry Habitats and the Xerophytes . . .569 



D. The Undrained Habitats and the Helophytes . .671 



E. The Saline Habitats and the Halophytes . . 573 



F. The Acid Soil Habitats and the Oxalophytes . . 673 



(3) The Organic Habitats and the Hysterophytes . . 574 



A. Habitats of Climbers . . . ... 575 



B. Habitats of Epiphytes . . . ... 676 



C. Habitats of Half -parasites 577 



D. Habitats of Parasites and Saprophytes . . .677 



E. Habit of Insectivorous Plants 578 



3. Plant Formations and Associations 579 



List of the Principal Formations .... 684 



