VARIATION IN THE FLORAL FRAGRANCE OF EPIDENDRUM-CILIARE (ORCHIDACEAE)

Variation in floral fragrance compounds might be a pollination strategy that disrupts associative learning processes and inhibits pollinator's ability to recognize non-rewarding flowers. Floral fragrances of the nectarless, moth-pollinated Epidendrum ciliare (Orchidaceae) were obtained from plants of Puerto Rico and the Virgin Islands. Fragrances were collected by passive diffusion on tenax adsorbent and analyzed using gas chromatography and mass spectrometry (GC/MS). The analysis was performed at six different levels: 1) by flower position on the same inflorescence; 2) by flower age on the same plant; 3) by position and age of the flower in the same plant; 4) by different shoots of the same plant; 5) by flowers from different plants; 6) and by plants from different populations. At no level of analyses were fragrances of sample pairs identical. The greatest similarity among fragrances was between flowers of the same plant. The most notable differences were between flowers of different populations. High levels of floral fragrance variation were consistent with the hypothesized deception pollination syndrome, but comparisons with reward-producing flowers remain to be done.