A preliminary survey of foliar sclerenchyma in neotropical Loranthaceae

The foliar sclerenchyma of all genera of neotropical Loranthaceae is surveyed by means of cleared leaves, using selected species. Three general categories of sclerenchyma are recognized. Fibers may form discontinuous or continuous bundles associated with veins or, more rarely, occur as individual cells. Sclereids, often of the astrosclereid type, are present in varying concentrations, or may be absent. Cristarque cells are very common, and occasionally extremely abundant, but are lacking in several genera. The survey includes information on terminal tracheids which are almost invariably present. Attention is drawn to the systematic significance of sclerenchyma where warranted.