7^ March, 



THE I.HAF- MARKING OF ARUM MACULATUM. 



BY NATHANIEI. COI.GAN, M.R.I. A. 



There are few Irish field botanists who have not been 

 impressed at one time or another with the singular infelicity of 

 the Linnean specific name for the Common Arum. Abundant 

 as the plant is throughout the greater part of Ireland, it is 

 only as a rather rare exception to the general rule that it 

 occurs with maculate leaves. One may spend day after day 

 botanising in the county of Dublin, where the species is 

 common over wide areas, without finding a single plant with 

 blotched leaves, and though our few local Irish Floras are 

 quite silent on this point, there seems to be a general agree- 

 ment amongst Irish field workers that the prevalent plant in 

 this island is one with immaculate leaves. English local 

 Floras are apparently no more explicit than our own. I have 

 consulted six of the best known English County P'loras and 

 found them all silent as to the marking of the Arum leaf. 

 From this silence a prevailing congruity of the English plant, 

 with its Linnean name, might be ingeniously deduced ; but a 

 reference to more general works is enough to throw grave 

 doubt on the conclusion arrived at by such a convenient 

 S3dlogisiic method. Lightfoot's Flora Scotica, 1777, tells us 

 that the Arum leaves are " often stained with dark or white 

 spots"; Bentham's Handbook, 1865, says they are "some- 

 times spotted with purple " ; Hooker's Student's Flora, 1884, 

 that they are '' often spotted black " ; and Babington's Manual, 

 1881, that they are "green or spotted with purple." The in- 

 ference to be drawn from the use of the words "often" and 

 "sometimes" in these passages is this, that in Great Britain, 

 as in Ireland, the Arum with immaculate leaves is the rule, 

 with maculate leaves the exception, though an exception of 

 more frequent occurrence than in Ireland. Personal inquiry, 

 not very exhaustive, indeed, tends to show that in Southern 

 Britain, at all events, maculate-leaved plants are frequent and 

 perhaps locally abundant. 



