A member of the Crataegus genus, hawthorn has a long history of medicinal use.

This potential hazard led us to investigate the suitability to leaf-curling aphids of alternative Crataegus species.

Ten Crataegus species characterized by their very low susceptibility to fire blight were examined from two angles.

They are allied to cratægus.

The possible causes of these negative results with respect to the geographical origin of the particular Crataegus species involved in this work are discussed.

In North America the numerous thorny species of Crataegus are equally vigorous, as are the false acacia (Robinia) and the honey-locust (Gleditschia).