JOURNAL OF THE ARNOLD ARBORETUM VOL. 56 JULY 1975 NUMBER 3 THE GENUS CLADOCOLEA (LORANTHACEAE) JOB KUIJT THE NEOTROPICAL GENUS Struthanthus (Loranthaceae) has never, in its existence of nearly a century and a half, been monographed or even sur-veyed in its entirety. Except for a few regional treatments of the genus, none of which extend north of Costa Rica, there has been little more than rather casual listing of species and the sporadic addition of what adds up to a great number of new names. Van Tieghem's work at the turn of the century added many new generic names to Loranthaceae in the Americas and elsewhere, and some of these genera are within what is now generally called Struthanthus. Little note has been taken of Van Tieghem's profusion of new genera except in rather isolated instances. A scrutiny of materials in most of the major herbaria of Europe andNorth America has shown that the insights of Van Tieghem and his no-menclatural creations can by no means continue to be ignored. This factis well illustrated by the present study. I have discovered that thereexists, mostly in central and southern Mexico, a group of related mistletoeswhich are so unusual, especially in their inflorescence morphology, thatgeneric status is fully deserved. The resultant genus, through the con-sistent use of accepted nomenclatural procedure, receives the name Cla-docolea Van Tieghem. Although Van Tieghem correctly perceived some ofthe unusual structural features of this genus, I hasten to point out thatmy conception of the outlines of Cladocolea has little in common withVan Tieghem's. Be that as it may, the present work embodies a mono-graphic treatment of Cladocolea. In the original description of Cladocolea (Van Tieghem, 1895a) someunusual features were listed. The flowers, unlike those of Struthanthusand most others, are single and develop in axillary positions. The spikesare axillary and often appear to break through the cortex of the mainstem, leaving an irregular craterlike rim. Van Tieghem erroneously de-scribed the flowers as hermaphroditic. While this condition exists in someother species, the species referred to by Van Tieghem are dioecious, al-though the flowers have rather large aborted organs of the opposite sex.Van Tieghem also failed to observe that the inflorescence of at least histype species, C. andrieuxii, was a determinate inflorescence, i.e., it ter-@ President and Fellows of Harvard College, 1975.