XX ‘ CONTENTS 
MEDULLARY RAYS.—Primary and Secondary; their structure, distri- 
bution and functions. . . . . OP eae ty Eas wea Ei 
VASCULAR AND FIBRO-VASCULAR BUNDLES.—Description of 
the various types; the distribution of each type; Xylem and 
Phloem. Leaf and branch traces. Recess 
THE STELE.—Definition. Prostele. Siphonostele. Dictyostele. 
Branch Traces. Leaf and Branch Gaps. ......-.-- 
SECRETION SACS.—Definition and distribution. . . . ..... 
INTERCELLULAR AIR SPACES.—Definition. Function. Schizo- 
genous and lysigenous air spaces; their relative size. . . 
INTERNAL SECRETION GLANDS AND RESERVOIRS.—Defini- 
tion; structure; internal glands; secretion canals; vitte. Their 
origin . pei mae 
PC AE i oe ee eg ee ee oe pe Ralls ie i 
CLASSIFICATION OF TISSUES ACCORDING TO FUNCTION . 
CHAPTER VII 
Tue Roor 
THE ROOT.—Definition; functions; rootlets; root hairs; piliferous layer; 
soil and water relation, diffusion, osmosis, osmosis applied to root 
hairs, turgor, plasmolysis, absorption of nutrient salts, essential 
elements and their importance, non-essential elements absorbed 
by root hairs; regions of the root (root cap, embryonic region, 
growing point, primary meristems or generative tissues, region 
of elongation, region of maturation and mature region). Differ- 
ences between root and stem . . . 
CLASSIFICATION OF ROOTS AS TO ORDER.—Primary root; tap 
root; secondary roots; fibrous and fleshy roots; prop roots; adven- 
titious roots; epiphytic roots; haustoria. ; 
CLASSIFICATION OF ROOTS AS TO FORM. ee napiform, 
conical fibrous, tortuous, nodose, moniliform, tuberous, fascicled 
ROOT CONSISTENCY OR TEXTURE. et roots. Fleshy roots: 
eRe tiie THEO ee te ae ot oe 
CLASSIFICATION OF PLANTS ACCORDING TO DURATION 
OF ROOT.—Annual; Biennial; Perennial . . ....... 
ROOT HISTOLOGY.—A, Monocotyledons: Histology of Similax root. 
B. Dicotyledons: Histology of Dicotyl roots: a. young growth, B. 
transitional growth and development of secondary structure. 
Histology and Development of the California Privet root. 
Abnormal structure of Dicotyl roots. shits of a Neots 
Tuberous Root (Aconitum). Root branching. 
ROOT TUBERCLES.—Definition; occurrence. | oie tubercles. 
Rotation of crops. e® tubercles; their etiology. Nitrogen 
CVE ko as 4 
sh SR Aes act MEN eR a es eee ey ee pee ahi? ov og aes 
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162 
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. 163-176 
176-182 
