CAMPBELL, LISA M.*, DENNIS WM. STEVENSON, AND GUSTAVO A. ROMERO-GONZÁLEZ. New York Botanical Garden, Bronx, NY 10458 and Harvard University Herbaria, 22 Divinity Ave., Cambridge, MA 02138. - Anatomical features of Aratitiyopea (Xyridaceae).
Aratitiyopea (Xyridaceae) comprises one species with two
subspecies that occurs at mid to high elevation on sheer rock faces
and waterfalls. It is known from a few populations on sandstone
mountains (tepuis) on the Guayana Shield of northern South America.
Unlike most Xyridaceae, Aratitiyopea is caulescent. The leaf
blades have a marked zone of articulation, and the persistent leaf
sheaths function as tanks accumulating water and debris. The escapose
inflorescence, unique in Xyridaceae, combined with the habit give the
plant a bromeliaceous appearance, and the species was originally
described as a Navia (Bromeliaceae). Aratitiyopea is
poorly known anatomically due to the paucity of preserved material. An
anatomical survey is being conducted on vegetative collections made in
January 2000 and compared to the other Xyridaceae. Preliminary results
show that leaf anatomy of Aratitiyopea is most similar to
Orectanthe, one of the other four genera in the family.
Key words: Anatomy, Commelinales, Xyridaceae