Abstract
Quantitative and qualitative data are presented for wood anatomy of the seven species of Cercidium (including two subspecies of C. floridum as well as the hybrid C. x sonorae) currently recognized. Data on wood of Parkinsonia are presented for purposes of comparison. Vessel walls of Cercidium show unusual sculpture: coarse excrescences termed verrucae here, crateriform pits, and grooves interconnecting pit apertures. These plus crystal distribution, presence of septa in fibers, pit diameter, presence of vasicentric tracheids, and presence of diagonal vessel aggregations are probably species distinctions to various degrees. The crystal-bearing fibers of Cercidium, some of which have very thin walls, exemplify fiber dimorphism. Wood of Parkinsonia aculeata is amply distinct from that of Cercidium. Vessel element dimensions and density in Cercidium do not indicate exceptional xeromorphy for woods, perhaps because some species grow in desert washes, perhaps because other features (leaflessness, thick cuticle on stems) reduce transpiration. Vessel wall sculpture, vasicentric tracheid presence, and degree of vessel grouping are considered likely indicators of wood xeromorphy within the genus, however.
Highlights
The report by Cozzo (1953) of crateriform pits in vessels of certain species of Cercidium led me to make preparations of the wood in order to illustrate these structures by means of SEM in a book (Carlquist 1988)
The coarse vessel wall excrescences of Cercidium are termed verrucae here because they are much larger than the structures termed vesturing by Ohtani et al (1981) or the structures often termed warts in conifer tracheids
More pertinent is the report of structures comparable to the verrucae of Cercidium in another genus ofFabaceae, Prosopis (Castro 1988)
Summary
The report by Cozzo (1953) of crateriform pits in vessels of certain species of Cercidium led me to make preparations of the wood in order to illustrate these structures by means of SEM in a book (Carlquist 1988). While examining sections of Cercidium wood under a light microscope, I discovered that protuberances could be found on vessel walls of some species. These structures provided an unusual opportunity for study by means of SEM, because adequate resolution of them could be achieved only by that means. The diversity ofwall sculpture in Cercidium was sufficient to make examination of all species desirable. The wood preparations of Cercidium revealed other anatomical features of interest, so a survey of wood anatomy of the genus has been undertaken here
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
