Arum maculatum

Caldecote Highfields, Cambridgeshire. Some plants have spotted leaves and others do not, see www.watsonia.org.uk/Wats3p181.pdf
The distribution of the spotted and unspotted leaf forms (var. immaculatum) has
been investigated by Pethybridge (1903) who gives the following results.
Sussex : 99 % unspotted
Hereford: 5 : 1 unspotted to spotted
Lincoln: 92 % unspotted
Northumberland : 90 % unspotted
Ireland: 500 : 1 unspotted to spotted

For more details see SOWTER, F. A., 1949, Arum maculatum, in BioI. FI. Brit. Is., J. Eco/., 37, 207. and the map reporduced n the above pdf.