10 ILLUSTRATIONS. 



Page. 



Fig. 11. Root of a wheat plant, showing the root hairs 40 



12. Portion of a wheat root, with root hairs 40 



13. Tip of the root hair of a wheat plant 40 



14. Root of a blueberry plant 41 



15. Root of a blueberry plant, enlarged 41 



16. Blueberry rootlet 41 



17. Mycorrhizal fungus of a blueberry plant densely crowded in two 



epidermal cells of the root 43 



18. Mycorrhizal fungus of Kalmia latifolia in an epiilermal cell of the root. 44 



19. Section of a blueberry seed 53 



20. Blueberry seedlings in the cotyledon stage 53 



21. Blueberry seedling about 6 weeks old, with five foliage leaves 54 



22. Normal tip of stem in a blueberry seedling 57 



23. Bract and young leaf at the end of the original stem in a blueberry 



seedling 58 



24. Blueberry seedling with diffuse type of branching 59 



25. Blueberry seedling of the type with few branches 59 



26. Spores of a supposedly injurious fungus in the epidermal cells of blue- 



berry roots 64 



27. Flowers of the blueberry, from 1908 seedlings of the large-berried 



New Hampshire bush of Vaccinium corymbosum 77 



28. Stamens of the blueberry 77 



29. Compound pollen grain of the blueberry 78 



30. Pistil and calyx of the blueberry, sh6wing the style and stigma 78 



31. Blueberry plant grown from a root cutting 86 



193 



