CONTENTS XV 



PAGES 

 THE ROOT. Definition; functions; root hairs; root cap; generative 



tissues; differences between root and stem 121-123 



CLASSIFICATION OF ROOTS AS TO FORM. Primary root; tap 

 root; secondary roots; fibrous and fleshy roots; anomalous 

 roots; adventitious roots; epiphytic roots; haustoria 123-124 



CLASSIFICATION OF PLANTS ACCORDING TO DURATION 



OF ROOT. Annual; Biennial; Perennial 124 



ROOT HISTOLOGY. A. Monocotyledons. B. Dicotyledons; Histol- 

 ogy and Development of the California Privet root; Abnormal 

 structure of Dicotyl roots; Histology of a Dicotyl Tuberous 

 Root, Aconitum 124-132 



ROOT TUBERCLES. Definition; occurrence on roots of Leguminosae, 



Myricaceae, etc.; their etiology 132-135 



THE BUD. Definition; plumule,, scaly buds, naked buds; Classifica- 

 tion of Buds According to Position on Stem: terminal bud; 

 axillary or lateral bud; adventitious bud; accessory bud. 

 Classification of Buds According to Development: leaf bud; 

 flower bud and mixed bud. Classification of Buds According 

 to their Arrangement on the Stem: alternate; opposite; 

 whorled 135-136 



THE STEM. Definition; direction of growth; functions; size; nodes 

 and internodes; stem elongation; duration of stems; stem 

 modifications; above ground stems; herb and tree defined; 

 underground stems; exogenous and endogenous stems. . . . 136-140 



STEM HISTOLOGY. Annual Dicotyl; Perennial Dicotyl; Excep- 

 tional Types of Dicotyl Stems; Lenticels and Their Forma- 

 tion; Annual Thickening of Stems; Method of formation; 

 "Annual Ring." Bark: Definition; zones; Periderm; Phello- 

 derm; Histology of Cascara Sagrada bark. Wood: alburnum; 

 duramen; microscopic characteristics of Angiospermous and 

 Gymnospermous woods; Histology of Typical Herbaceous 

 Monocotyl Stems; Histology of Typical Woody Monocotyl 

 Stem 140-154 



THE LEAF. Definition; leaf functions: photosynthesis; assimilation; 



respiration; transpiration 155 



TYPES OF LEAVES DEVELOPED IN ANGIOSPERMS. Cotyle- 

 dons; Scale leaves; Foliage leaves; Bract leaves: bracts and 

 bracteoles; Sepals; Petals; Microsporophylls; Megasporophylls 155-156 



