<p>The family Asteraceae possesses a remarkable variety of trichomes which led to the use of the same name for different types of trichomes and different names for the same type of trichome. Light microscope observations of vegetative and reproductive organs of ca. 135 genera of Asteraceae were surveyed. Additional information on the trichomes of Asteraceae and other plant families was obtained from the literature. Some terms that are frequently misused, misunderstood, or employed as synonyms were clarified, the trichomes were classified and illustrated and the existing terminology was standardized. Seventeen trichome types and 25 subtypes were established: 1) Glandular trichomes: uniseriate (subtypes simple, bladder head); biseriate (subtypes simple, bladder head); multiseriate (subtypes simple, hollow-stalked, tack-shaped). 2) Non-glandular trichomes: unicellular; one-armed (subtypes simple, barnadesioid); filiform; flagelliform; conical; cylindrical; moniliform; two-armed (subtypes T-shaped, antler-shaped, L-shaped, Y-shaped); three- to more-armed (subtypes antler-shaped, stellate); scale; dendritic (subtypes ramose, bristly); multitiered (subtypes multi-two-armed, multistellate). 3) Twin trichomes: subtypes basic; asymmetric; divergent; crenate; radiate; one hair-celled. 4) Papillae. Synonymies and a key to trichomes are presented.</p>