422 
Hill . — Studies in Seed Germination . 
Passing now to the behaviour of the cotyledonary and plumular leaves 
when subjected to artificial mutilation, some striking differences are notice- 
able, as Winkler and Goebel 1 have pointed out. 
If the lamina of the first cotyledon be removed, there will arise, from one 
or from both the ridges on the inner side of the petiole, just below the cut 
surface, small protuberances which will gradually develop into new laminae. 
The new laminae grow out from the petiole as decurrent wing-like 
organs, and like the lamina are bifacial with their upper surfaces facing 
Fig. 6. 
Fig. 7. 
Fig. 5. 
Text-figs. 4-7. 4. C.persicum. The petiole of the normal cotyledon with the lamina removed. 
A new lamina, /. 2, has developed from the edge of the groove of the petiole near the cut surface. 
Back and front views. 5. C. balearicum. The formation of new laminae, /. 2* from the cotyledonary 
petiole. 6. C. persicum. The new lamina, l. 2, has developed a petiole and the lamina has been 
removed. 7. The development of new laminae, /. 3, from the secondary petiole. 
inwards. These new laminae are thus in their position at right angles to 
the original lamina of the cotyledon. Sometimes they remain as longitu- 
dinal wings or flanges attached by a broad base to the upper part of the 
petiole, but more often they assume the form of small leaves and develop 
distinct petioles of their own. 
If after a time the upper part of the original petiole with the new 
laminae be removed, the petiole will again produce new laminae just below 
the cut surface, and it has been found that even if as much as 6 mm. of the 
apical portion of the cotyledonary petiole be removed new laminae will be 
and also in double bundles, the protoxylems may be more or less united, so that an apparently 
single, rather diffuse, protoxylem group may occur on the adaxial side of the bundle.’ 
1 Winkler: Ueber die Regeneration der Blattspreite bei einigen Cyclamenarten. Ber. d. Deut. 
Bot. Gesellsch., xx, 1902, p. 81. 
Goebel: 1 . c., 1902, pp. 436-8, Figs. 10-13; and 1 . c., 1908, p. 203, Fig. 105. 
Similar experiments were made by me at Cambridge in 1907 and 1908 on Cyclamen balearicum 
and C. neapolitanum independently of Winkler’s and Goebel’s work. 
