LIST OF ILLUSTRATIONS xi 



FIG. PACK. 



82. A panicle of oats, with weak branches, photographed at 



Svalof, Sweden . . . . . . .273 



83. A panicle of oats with stiff branches, photographed at 



Svalof, Sweden . . . . . . .275 



84. A spikelet of oat-grass (Avena elatior), showing a flower 



with two palets, three stamens, and two stigmas (a), a 

 flowerbud (b), of which only the palets are visible, 

 and the third or sterile flower (c) . . . .278 



85. Barley. A. A complete spikelet with the three flowers. 



B and C. Single flowers seen from different sides, show- 

 ing two palets, three stamens, and the ovary with the 

 stigmas. In B, also the two outer scales or glumae. D. 

 Stamens and ovary of a flower . . . -279 



86. Svalof Solo pea, a new forage-plant, most productive of 



seeds and foliage. Leaves green . . . .281 



87. Svalof Grop pea, a new early ripening forage-plant . -283 



88. The wild oat-grass (AiJena elatior), a pasture grass . . 285 



89. A pitcher-like leaf of tobacco . . . . .291 



90. Pitchers of Magnolia, A, B, C. Of clover, D, E. Of 



the lime-tree (Tilia), F, G. One-leaved pitchers. 



C. Two-leaved. A. Upper part of a leaf only trans- 

 formed into a pitcher. D, E. Pitcher-like leaflets of 



the ordinary and of the five-leaved clover . . 293 



91. A. Seedling-plants of Evening Primroses. B. Of the fig- 



wort (Scrophidaria nodosa). C. Of Silene odontipetala. 



D. Of poppies. E. Of the beech. A i and D i. Nor- 

 mal seedlings. A 7, B, C 2, D 4, E, Tricotyledonous 

 seedlings. C 3, D 5, Seedlings with four and D 6 with 

 five seed-leaves. A 2-6, C i, D 2-3, Different degrees 



of splitting of seed-leaves ...... 295 



92. Polycephalous opium poppy. A. Normal fruit. B. The 



same cut longitudinally. C, D. Normal stamens. E, F. 

 Stamens transformed into secondary carpels. G, H, I. 

 Secondary carpels, cut transversely with one, two, and 

 four rows of seeds ....... 299 



93. Young plant of opium poppy in the sensitive period of the 



development of the terminal flower, cut longitudinally. 

 A. Flower-head of June 7. B. Of June 14. C. All parts 

 discernible. D. Diagram of flower. E. Diagram of 

 young flowerbud. P. Petals. S. Stamens . . 301 



94. The Double Corn-marigold, an experimentally produced 



variety ......... 303 



95. Variability in the size of the ripe fruits of the Evening 



Primrose of Lamarck. A. A weak plant with small 

 fruits. B. A tall plant with large fruits . . 305 



96. A. The Pansy and some of its parents. B. Viola lutea 



yrandiflora. C. Viola tricolor versicolor. D. Viola tri- 

 color lutescens. After Wittrock . . . . 311 



