Index . 
xm 
Figures. 
page 
tuber has formed from the cell mass developed at proximal end. The 
scar (sc.) is almost obliterated. 9 A. Leaf as collected. 9 b. Same 
after seven weeks on moist soil, n A. Leaf as collected. 11 b. Same 
after seven weeks on moist soil. 12 A. Leaf with unusually large 
cell mass formed at ground-level, also stalk with growing-point 
beginning to elongate. 12 b and c. Same viewed from proximal end. 
13. Single-leaved plant forming adventitious cell mass on leaf above 
injury, also new tuber; current tuber not shown. Fig. 14. Three- 
leaved plant with cell mass forming from proximal end of broken 
leaf (Osborn) 492 
1 5. Three-leaved plant grown in laboratory. One leaf, injured July 17, 1918, 
has developed an adventitious tuber (Osborn) .... 494 
16-22. Leaves of Series B, detached and put on soil July 11, 1918. The dates 
below in brackets are those on which the figures were drawn. 16 A. 
Cell mass forming (Sept. 16). 16 b. Same with adventitious tuber 
(Nov. 16). 17 a. Growing-point just visible on cell mass (Sept. 16). 
17 b. Same, showing elongation of stalk (Sept. 24). 18 a. Cell 
mass with rhizoids and short stalk bearing growing-point (Sept. 16). 
1 8 b. Same developing two growing- points from cell mass, also 
‘leaflet’ (Sept. 26). 18 c. ‘Leaflet’ enlarged, two tubers forming 
(Oct. 8). 18 D. Same : tubers are smaller and less regular than those 
formed singly by other leaves of the same series. Rhizoids absent 
(Nov. 16). 19 A. Small cell mass, stalk, and growing-point 
(Sept. 16). 19 b. Same (Nov. 16). 20 A. Portion of leaf showing 
cell mass. Leaflet stalk and tubers beginning to swell. No rhizoids 
at this date (Oct. 8). 20 B. Same original leaf beginning to rot 
(Nov. 16). 21 and 22. Two remaining leaves of series (Nov. 16) 
(Osborn) 496 
23-29. Leaves of various series. The dates below in brackets are those on 
which the various figures were drawn. 23. Leaf of Series C. The 
cell mass is nodulose ; a transverse section of this leaf is seen Fig. 38 
(Sept. 24). 24 a and b. Leaf of Series C. This leaf curved on 
soil in horizontal plane. Adventitious growth from convex side 
(Nov. 16). 25. Leaf of Series D. Note absence of definite growing- 
point and formation of many starchy cell masses (Oct. 21). 26-29. 
Leaves of Series E (Nov. 25) (Osborn) 499 
30-35. Leaves of Series A, detached and put on soil June 13, 1918. The dates 
below in brackets are those on which the figures were drawn. 30. 
Adventitious tuber arising from side (Nov. 16). 31. Extreme case 
of leaf curvature in vertical plane. Cell mass nodular (Sept. 16). 
32 A. Leaf showing vertical curvature. This leaf appears to be an 
exception to rule that adventitious growth occurs from convex surface 
(Sept. 16). 32 B. Same, viewed from above ; note nodular develop- 
ment of cell mass. This leaf was laid flat on soil Sept. 16 (Oct. 21). 
32 c. Same ; note many short-stalked, white, swollen bodies 
(Nov. 27). 33 A. Leaf viewed from above, and B, viewed from side, 
showing geotropic curvature of the many minute, stalked tubers 
(Nov. 27). 34 A. Leaf viewed from above, and B, viewed from below 
(Nov. 26). 35. Portion of leaf, viewed from side, with several 
scattered centres of adventitious growth. Two have developed leaf- 
lets and small tubers (Nov. 17) (Osborn) 502 
36. Portion of transverse section of leaf showing adventitious growth from 
single epidermal cell. Stomate seen to left (Osborn) . . . 503 
37. Transverse section of leaf showing considerable cell mass of epider- 
mal origin, interrupted by stomate at St. Growth is becoming 
localized by development of growing-point seen at right (Osborn) . 503 
