THE 
NEW PHYTOLOGIST 
Vol. XXII. No. 2 May 19, 1923 
AN EXAMPLE OF LEAF-ENATION IN ALLIUM 
URSINUM L. 
By S. L. GHOSE, M.Sc. (Panjab) 
Selwyn College, Cambridge 
I N May, 1922 the late Mr Arthur Shrubbs, of the Cambridge 
Botany School Museum, found an interesting example of a leaf of 
Allium ursinum L., which had developed a second “lamina” on the 
lower surface. It was found growing on a boggy patch of ground near 
the Whittlesford Railway Station, about eight miles from Cambridge. 
Unfortunately, the specimen as brought into the laboratory was not 
complete, as the underground portion of it was left behind. In spite 
of a careful search by me in the same place a few days afterwards, 
the underground portion could not be discovered on account of the 
thick undergrowth, nor was any other similar specimen found. It 
was suggested to me that the vascular anatomy of the leaf might 
be interesting to work out, so I gladly undertook to do it. This paper 
embodies the result of the investigation. 
According to Mr Shrubbs’s observation, the leaf while on the plant 
took up nearly an upright position, so that both its surfaces were 
turned more or less towards the light. “ Petiole ” and “lamina” were 
alike abnormal in structure. The “petiole,” instead of being semi¬ 
circular in section, as in normal examples of Allium ursinum , was 
flattened and appeared as if made up of two fused “petioles.” In a 
transverse section at the base of the aerial region it showed three 
prominent “ribs,” one central and two marginal (Fig. 2). The central 
one continued into the “laminar” portion as the “midrib,” and 
developed on the lower side the second blade. This lower blade was 
formed up to the very apex of the leaf, but was only half as broad 
as the upper one. The two marginal ones continued into the upper 
blade up to the very apex and formed two lateral prominent “ribs” 
Phyt. xxii. 2. 
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