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Vestured Pits In Echium (Boraginaceae): Island Woodiness Revisited, Sherwin Carlquist

Aliso: A Journal of Systematic and Floristic Botany

Vestured pits are present on pits of secondary xylem vessels of all studied Echium species, roots as well as stems. Variations in vesturing presence do occur in the genus (across wide circular pit cavities; along margins of elliptical pit apertures; aggregated to various degrees; variously abundant), but these are difficult to define precisely and are related primarily to organography and ecology rather than to the taxonomic system. The Macaronesian species have been reported to form a single clade. Wood anatomical features other than vesturing are also closely keyed to species ecology and, in particular subclades, growth forms. Woodiness, exemplified by …