viii CONTENTS 



CHAPTER PAGE 



IV. Mechanical Problems: Protection .... 283 

 I. Mechanical Problems, 283. Mechanical Tissues, 283. 

 Mechanical Features of the Root System, 286. Mechanical 

 Features of the Stem, 288. Mechanical Features of Leaves, 

 292. Aquatic Plants, 293. Climbing Plants, 295, II. Pro- 

 tection against Animals and against Other Plants, 306. 



V. Reproduction and Dispersal 314 



General Considerations, 314. Sexual and Asexual Repro- 

 duction, 318. Seed Formation, 324. Parthenogenesis and 

 Apogamy, 326. Sex Distribution in Flowering Plants, 329. 

 Determination of Sex, 332. Changes in Sex Distribution in 

 the Course of Evolution, 338. Secondary Sex Characters, 

 339. Pollination — the Stamens and the Pollen, 340. Polli- 

 nation and Fertilisation, 352. Pollination — Agencies, 354. 

 Pollination— Floral Mechanisms, 379. Cross-Pollination, 

 382. Self-Sterility, 391. Self-pollination, 394. Pollination 

 — General Considerations, 398. The Seed and the Fruit, 

 399. Dispersal, 407. 



VI. Development • 4^8 



Vitality of Seeds, 418, Dormancy of Seeds, 422 Viviparous 

 Seeds, 431. Germination — Conditions, 432. Germination 

 — Liberation of the Embryo, 433. Germination — Emergence 

 of the Seedling, 436. Mode of Growth, 439. External 

 Conditions and Growth, 443. Development — The Vege- 

 tative Phase, 444. Seasonal Changes, Protection, and 

 Rhythm, 447. The Reproductive Phase, 457. Senescence, 

 Death, and Individuality, 459. 



BIBLIOGRAPHY 465 



INDEX OF PLANT NAMES .501 



SUBJECT INDEX 516 



