Trichomes of Hedera L. taxa have long been used as an important character in delimiting species. Hedera exhibits two distinct trichome types: scale-like and stellate. This study examined the trichome variation in sixteen currently recognized Hedera taxa using scanning electron microscopy. Measurements of trichome morphology were taken, and variation among taxa compared. Of the taxa with scale-like trichomes, H. maderensis Rutherford subsp. maderensis has the largest overall length, longest rays, and largest fusion of rays. Of the species with stellate trichomes, H. helix has the largest overall, and also has the longest rays and widest rays.
