XX CONTENTS. 



PART III. 

 ECOLOGY. 

 INTRODUCTION. page 300 



CHAPTER XLIV. 



WINTER buds; growth of woody shoots; leaf arrangement. 



Winter buds and how the young leaves are protected, 564. 

 Twigs and buds of the horse-chestnut, 565. Leaf scars, 566. 

 Lateral buds, 567. Bud leaves, 568 Opening of the buds 

 in the spring, 569. Growth in thickness of woody stems, 

 571. Difference in the firmness of the woody rings, 575. 

 Annual rings in woody stems. 576. Phyllotaxy or arrange- 

 ment of leaves, 579 page 302 



CHAPTER XLV. 



SEEDLINGS. 



The common garden bean, 584. The castor-oil bean, 585. How 

 the embryo gets out of a pumpkin seed, 586. Arisamci 

 triphyllum, 588. Germination of the seed of " jack-in-the- 

 pulpit," 588. How the embryo backs out of the seed, 589. 

 How the first leaf appears, 591. The first leaf of " jack-in- 

 the-pulpit " is a simple one, 592 page 307 



CHAPTER XLVI. 



further studies on nutrition. 



Nutrition in lemna, 594. Spirodela polyrrhiza, 595. Nutrition 

 in wolffia, 596. Nutrition in lichens. 597. Nitrogen 

 gatherers, 599. How clovers, peas, and other legumes 

 gather nitrogen, 599. A fungal or bacterial organism in 

 these root tubercles, 600. How the organism gets in the 

 roots of the legumes, 601. The root organism assimilates 

 free nitrogen for its host, 602. Mycorhiza, 603. Nutrition 

 of the dodder, 605. Carnivorous plants, 606. Nutrition of 

 bacteria, 607 page 31^ 



