CONTENTS 
176. The measurement of responses to light 
Adaptation 
177. Influence of chloroplasts upon form and structure 
178. Form of leaves and stems . 
179. Modification of the epidermis 
180. The differentiation of the chignenchomn 
181, Types of leaves . 
182. Heliophytes and sciophytes. 
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EXPERIMENTAL EVOLUTION 
183. Scope . ‘ : 
184. Fundamental lines of i inquiry 
185. Ancestral form and structure 
186. Variation and mutation 
187. Methods 
Method of Natural Experiment 
188, Selection of species 
189. Determination of factors 
190. Method of record 
Method of Habitat Cultures 
IgI. Scope and advantages 
192. Methods . 
193. Transfer 
194. Modification of the habitat . 
Method of Control Cultures 
198. Scope and procedure . 
196. Water-content series . 
197. Light series 
CHapter IV. Tue ForRMATION 
METHODS OF INVESTIGATION AND RECORD 
198. The need of exact methods . 
Quadrats 
199. Uses . 
200. Possible ih ertons 
Kinds of Quadrats and Their Use 
201. Size and kinds 
202. Tapes and stakes 
203. Locating quadrats 
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