Pubescence, floral temperature and fecundity in species of Puya (Bromeliaceae) in the Ecuadorian Andes.

The effects of inflorescence pubescence on floral temperatures and fecundity were examined in four species of Puya in the Ecuadorian Andes. These species span an elevational range from 1,980-4,000 m and comparisons among these species showed that pubescence production increases significantly with elevation. Flower temperatures of glabrous or slightly pubescent species of Puya from lower elevations closely tracked air temperature, while those of the pubescent páramo species did not. Pubescence removal experiments on Puya hamata, a páramo species, demonstrated that pubescence is an effective insulator, maintaining elevated flower temperatures. In Puya clava-herculis (also a páramo species) elevated flower temperatures were associated with higher seed set. Thus, the greater production of inflorescence pubescence in páramo species of Puya may be an important factor contributing to reproductive success in these higher elevation species.