Wood anatomy and relationships of Stackhousiaceae

CAIU.QUJST, S.: Wood anatomy and relationships of Stackhousiaceae. Bot. J ahrb. Syst. t 08: 473-4BO. 1987. ISSN 0006-8152. Quantitative and qualitative features are described for five species of Stackhousia. The imperforate tracheary elements are all tracheidlike fiber-tracheids. Very narrow fusiform vessel elements are present. All other vessel elements are relatively narrow, and numerous per mm2 of transection. AU of these features connote xeromorphy. Quantitatively the xeromorphy is not extreme, a fact thought to relate to the habit in Stackhousia of stems to die back to a woody base annually, as well as to drought-deciduous nature of foliage and short-lived natured of plants. Wood features of Stackbousia are compatible with the concept that the family belongs to Celastrales. Possession of fiber·tracheids, as well as other features, favor this hypothesis over the idea of re.lationship to Scrophulariaceae or Lobeliaceae.