Studies in Seed Germination. 
Experiments with Cyclamen . 1 
by / jun 
ARTHUR W. HILL, F.R.S. 
With Plate XX and fifteen Figures in the Text. 
T HE question as to whether the seedling of Cyclamen is ‘ monocotyle- 
donous ’ or 4 dicotyledonous 5 has attracted the attention of numerous 
botanists, and up to the present may still be regarded as being an open one. 
Bernhardi 2 in 1832 made the suggestion that the single seed-leaf of Cyclamen 
represents two fused leaves, basing it on the analogy of the tube formed by 
the two cotyledons of Dodecatheon ; Lord Avebury also observed that 
abnormal seedlings of Cyclamen may have divided leaf-blades ; 3 but neither 
of these views need be seriously considered as tending to prove that the 
single cotyledon of Cyclamen is really a double structure. 
The late Miss Sargant 4 remarked that the 4 vascular structure ’ of 
Cyclamen persicum 4 suggests very strongly that the cotyledonary member 
consists of two seed-leaves united into a solid tube but, she added, 4 until 
the structure of allied genera has been worked out no great weight can be 
attached to this observation \ 
The main purpose of the present paper is to give an account of some 
experiments and observations made on several species of Cyclamen , which, 
\ it is considered, afford definite proof that the embryo of Cyclamen does 
possess two cotyledons, only one of which, however, under normal condi- 
tions, develops into a leafy structure. 
The opinions held by the earlier botanists on the nature of the 
Cyclamen seedling have been so well summarized by Gressner 5 that they 
need no further reference here. Notice, however, must be taken of 
1 Read before the Linnean Soc., June 6, 1918. See Proc. Linn. Soc., June 6, 1918. 
2 Bernhardi : Linnaea, vii, 1832, p. 578. 
3 Lubbock, Sir J. : A Contribution to our Knowledge of Seedlings, ii, 1892, p. 184. The 
double-leaved seedlings were no doubt specimens in which the original lamina had been injtired and 
had been replaced by two new> laminae produced from the top of the petiole. 
4 Sargant, E. : A Theory of the Origin of Monocotyledons founded on the Structure of their 
, Seedlings. See Ann. Bot., xvii, 1903, p. 76. 
5 Gressner, H. : Bot. Zeit., 1874, p. 801, with plate. 
[Annals of Botany, Vol. XXXIV. No. CXXXVI. October, 1920.] 
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