Critical Observations on the Parasitism of New World Mistletoes

The parasitism of the mistletoes of the Americas is surveyed and integrated with recent observations on haustorial structure and mode of attack of the mistletoes of Central America and California. The occurrence and behavior of epicortical roots is traced in the genera Struthanthus, Phthirusa, and Antidaphne. Special consideration is given to the gross structure and development of the primary haustorial contact. A final section deals with the parasitism of mistletoes on leaves, on other mistletoes, and on themselves.