Origin and nature of vessels in Monocotyledons. 7. Philydraceae and Haemodoraceae

Abstract

Abstract Schneider, E. L. and S. Carlquist (Santa Barbara Botanic Garden, 1212 Mission Canyon Road, Santa Barbara, CA 93105). Origin and nature of vessels in monocotyledons. 7. Philydraceae and Haemodoraceae. J. Torrey Bot. Soc. 132: 377–383. 2005.—SEM studies of macerated stems and roots showed that long scalariform perforation plates are present in roots and probably also stems of Philydrum (Philydraceae). In Haemodoraceae, clearly recognizable vessel elements are present in roots; perforation plates range from scalariform to simple. In stems of Haemodoraceae, however, less clearly recognizable vessel elements are present: the presence of threadlike pit membrane remnants is one criterion that argues for vessel presence. Such tracheary elements can be considered transitional between tracheids and vessel elements. End walls of transitional tracheary elements may have narrower bars between perforations, less prominent borders, and pit membrane remnants rather than nonporose pit membranes. However, only one...