CARLQUIST, S. AND EDWARD L. SCHNEIDER.* Santa Barbara Botanic Garden, 1212 Mission Canyon Road, Santa Barbara, CA 93105. - Anatomical studies of Amborella.
As reported by Bailey and Swamy, Amborella has tracheids that
tend to have scalariformly pitted end walls but smaller oval to
circular pits on lateral walls. SEM studies of tracheids from both
sections and macerations reveal that there are small pores in the end
wall pit membranes, but pore size is smaller than in dicots with
vessels that contain porose pit membrane remnants in perforations
(e.g., Illicium). The size difference is not sharply
different, showing that tracheids and vessels, although identifiable,
are close to being an intercontinuous system. Amborella is
alleged to lack mucilage/oil cells, but thin-walled sclereids
containing sphaeroidal non-staining contents are present in leaves.
Anatomy of Amborella is compatible with the concept of a
relationship to Illiciales (s. l.)
Key words: Amborella, Illiciales, tracheids, wood anatomy