GARDNER-SILL, C. S. Georgia Southern Botanical Garden, P. O. Box 8039, Statesboro, GA 30458. - Characteristics from living flowers improve classification of Tillandsia (Bromeliaceae).
Today, relationships among species are assessed by molecular
techniques, including dna sequencing. Tillandsia, a large,
morphologically diverse and mostly epiphytic neotropical genus that
includes nearly one quarter of the species in the entire family, is,
however, still in need of alpha-taxonomic investigation. Previous
treatments of the 400+ species of Tillandsia were based on
characters found on herbarium specimens. Since dried flowers in these
species preserve poorly and are sometimes absent, floral characters
are difficult to observe in this manner. Smith and Downs were able to
find only one character by which to distinguish subgenus
Allardtia from subgenus Tillandsia (together 269
species) in their treatment of the Tillandsioideae for Flora
Neotropica–whether the stamens were included (Allardtia) or
exerted (Tillandsia). Previous field studies of 79 species of
subgenus Tillandsia and 12 species of subgenus Allardtia
in Mexico showed that rather than two natural groups, five distinct
groups could be circumscribed by suites of characters from fresh
flowers, and that these groups cut across current taxonomic lines.
Subgenus Tillandsia has its center of distribution in Mexico,
while subgenus Allardtia is largely centered in the Andes of
South America. Current field studies in Ecuador are expanding the
number of species examined and support the hypothesis that a thorough
examination of flowering specimens in vivo of the majority of the
species in these two subgenera can result in a more natural
classification for this difficult group.
Key words: Bromeliaceae, Bromeliads, classification, floral characteristics, taxonomy, Tillandsia