Some Ornamental Plants Excreting Respiratory Irritants

Many people who suffer from seasonal inhal ant allergy in other sections of the United States, come to Florida to escape from offensive pollens at home, inasmuch as airborne pollen grains are commonly declared to be the princi pal exciting cause of such respiratory afflictions, and change of regional residence has in many cases brought relief (7). However, some vic tims who migrate to South Florida find their condition worsened by unanticipated plant airpollutants in this environment. Lillian Beaman Fly, formerly Assistant Pro fessor of Botany, University of Miami, once made a year-long survey of airborne viable mold spores of South Florida and an exhaustive, 10year study of the distribution of potential allergenic pollens of this area. She also made a 3year study, in cooperation with local allergists, of the comparative antigenicity of selected pol lens and mold spores of South Florida. It be came apparent to her that the mango tree (Mangifera indica L.) though a major cause of widespread respiratory difficulty when in bloom, has sticky, non-windborne (anemophilous) pol len. This is confirmed by the experiments of R. W. Lakhanpai and P. K. K. Nair who carried out a "Survey of the Atmospheric Pollen at Lucknow," India, "over a period of one year commencing from 1 October 1954." In their words, "The pollen were caught daily on a mi croscope slide smeared with glycerine jelly and exposed to the atmosphere at a height of about 25 ft. above the ground level. . . . One surprising fact is that although Mangifera is a very com mon tree in Lucknow, not a single pollen grain of this plant was trapped . . ." (14). The mango tree is a member of the Anacardiaceae and accordingly related to poison ivy and poison sumac, and the sap and other parts of the tree and the peel of the fruit are common causes of dermatitis and even more serious re actions. Particularly sensitive individuals suffer swelling of the eyelids, facial burning and rash through proximity to blooming trees without di rect contact (17). It seems logical to assume that the inflorescence disperses into the atmos phere a substance, possibly similar to the urushiol of poison ivy, affecting the skin and the respiratory passages of many persons. Not only allergists but general practitioners treat many patients for respiratory difficulty during mangoblooming season (particularly January-Febru ary-March) in South Florida. The subdividing of some mango groves into homesites is bound to bring more hypersensitive individuals and blooming mangoes into juxtaposition. In 1957, Mrs. Fly took preliminary steps to trap and study the offensive emanation from the mango bloom, but lack of financial support for such research prevented her pursuing it.