The flowers of Cyclamen coum are dumpy and have no auricles at the base. The flowers of Cyclamen hederifolium are more elongated and have auricles. The leaves are also different, Cyclamen coum has rounded leaves and Cyclamen hederifolium more pointed. Cyclamen coum flowers early in the year and Cyclamen hederifolium flowers from late summer to autumn.
Cyclamen coum flowers and leaves.
Cyclamen hederifolium flowers and leaves.
David Pilling adds more details.
An auricle is an ear like projection.
The name hederifolium derives from the Latin name hedera for ivy because of the leaf shape. On the other hand coum comes from the Hebrew name for this species; it is mentioned in the Mishnah as being used as a source of dye; the common name 'round leaved cyclamen' is more help for identification.
Photograph 1 is of Cyclamen coum leaf bottom left and Cyclamen hederifolium leaves. Photo 2 by Caroline Langensiepen shows Cyclamen hederifolium leaves can grow large as the ruler in the photo which measures 7 inches.