Wood Anatomy of Nolanaceae

Abstract

Wood of seven collections of six species of Nolana, a genus (18 spp.) of the central western coast of South America was studied for quantitative and qualitative features. The wood is ring porous, with moderately wide vessels bearing simple perforation plates and alternate pits with some grooves in terconnecting slitlike pit apertures. Imperforate tracheary elements are fiber-tracheids with vestigial borders on pits or libriform fibers; vasicentric tracheids (reported for Nolanaceae for the first time) are present in varying numbers. Axial parenchyma is vasicentric scanty (sometimes absent), sometimes with tangential bands that may be terminal in part. Rays are both multiseriate and unisenate; ray cells are mostly erect. Crystal sand occurs in some ray cells and some axial parenchyma. The sum of features mark Nolanaceae as very close to Solanaceae. Wood of Nolana varies in xeromorphy; lower degrees of xeromorphy may be explained by succulence related to maritime habitat or to ephemeral nature of stems. The erect nature of ray cells and a decrease in vessel element length are indicators of paedomorphosis and thereby herbaceousness of Nolanaceae.