Hill. — Studies in Seed Germination. 
419 
persicum in connexion with the regeneration of the lamina from the cotyle- 
donary petiole. His interpretation of the Cyclamen seedling is not very 
clear, but he definitely states that the genus differs from other Dicotyledons 
in not possessing two cotyledons (1. c., p. 435), but only a single seed-leaf. 
It is on this single seed-leaf or cotyledon that Goebel carried out his 
regeneration experiments, and he makes no reference to the development of 
a second cotyledon. He states, however, that in all his experiments he 
removed ‘the second leaf’, but whether this second-appearing leaf was 
actually the second cotyledon or, more probably, the first plumular leaf is 
not certain. He refers to the leaves which arise after the cotyledon as the 
first leaves, ‘ Primarblatter ’, whatever their morphological nature may be, 
and there is no evidence that he distinguished between the true second 
cotyledon and the subsequent plumular leaves. 
In the course of this paper I have pointed out that the regeneration of 
a lamina from the petiole is a peculiarity possessed by the cotyledonary 
petioles only, and Goebel also notes (p. 438) that he was unable to obtain 
regeneration with the older leaves of plants of flowering age. He appears 
to state, however, in a sentence, 1 the exact meaning of which is somewhat 
obscure, that the leaves following the ‘ single * cotyledon have similar 
powers of regeneration to that organ. These leaves, which he calls the 
‘Primarblatter’, should be the plumular leaves, and with such I find no 
regeneration of the lamina takes place. Possibly he may have experimented 
with the second leaf of a seedling which did happen to be a true second 
cotyledon, otherwise I am unable to reconcile his conclusion. 
Winkler 2 also, it may be mentioned, shows no particular interest in 
the question of the monocotyledonous or dicotyledonous character of the 
Cyclamen seedling, since his experiments are concerned with the behaviour 
of the first seed-leaf under traumatic stimulation, but it may be inferred 
from his account that he considers Cyclamen to be possessed of only a single 
cotyledon. 
A preliminary account of my own experiments with reference to the 
development of the second cotyledon of Cyclamen was given at the meeting 
of the British Association at York in 1906. 3 
The Cyclamen seedling, as is well known, consists of a short hypocotyl 
— the young tuber or corm — bearing at its apex two organs placed exactly 
1 p. 438 : ‘ Bei den Regenerationsversuchen, die oben kurz gescliildert wurden, entfernte ich das 
zvveite Blatt meist sobald es sichtbar war, iibrigens verhalten sich die dem Kotyledon folgenden 
Blatter betreffs ihres Regenerationsvermogens ebenso wie diese ’ (sic). 
2 H. Winkler : Ueber die Regeneration der Blattspreite bei einigen Cyclamenarten. Ber. d. 
Deut. Bot. Gesellsch., xx, 1902, p. 82. 
3 In the course of my experiments, which were commenced at Cambridge in 1904, I have 
examined the seedlings of Cyclamen Atkin si, C. balearicum , C. Count , C. libanoticum , C. neapoli - 
tanum , and C. persicum. Figures of the seedlings of several species of Cyclamen are given by 
Hildebrand, 1 . c. See A. W. Hill: The Seedlings of certain Pseudo-monocotyledons. Report Brit. 
Assoc. York, 1906, p. 763. 
F f 2 
