POLLINATION OF PTEROGLOSSASPIS-RUWENZORIENSIS (RENDLE) ROLFE (ORCHIDACEAE) BY BEETLES IN ARGENTINA

Beetle pollination by Euphoria lurida (Scarabaeidae: Cetoninae) is doc umented far Pteroglossaspis ruwenzoriensis (Orchidaceae: Epidendroidea e: Cymbideae: Eulophiinae) in its natural habitat in Central Argentina (South America). Flower features with special emphasis on those relat ed to beetle pollination are given. These include: long rigid and well exposed inflorescences, sturdy inconspicuous and deep flowers with sm all entrance, emission of a yeast-like fragrance, jelly-like nectar, s hort column, and a head-attaching pollinarium with a broad saddle-like viscidium. Pollinator behaviour and pattern of flower opening favour cross pollination and probably long distance pollen dispersal. Floweri ng, which lasts about 3 weeks, peaks in summer past mid-January. In na tural conditions about 68 flowers are pollinated for every 100 pollina ria removals.