Distinctive wood anatomy of the root-parasitic family Lennoaceae (Boraginales)

Publication Type:Journal Article
Year of Publication:2017
Authors:Carlquist, S, C. Guilliams, M
Journal:IAWA Journal
Volume:38
Pagination:3–12
ISSN:2294-1932
Keywords:Ecological wood anatomy, holoparasites, perforation plates, succulent plant anatomy
Abstract:

The four species of Lennoaceae have strands of primary plus secondary xylem in a background of starch-rich parenchyma. These strands constitute a cylinder with large primary rays. The wood within these strands is markedly different from that of other families in the crown group of Boraginales such as Cordiaceae and Ehretiaceae, most of which are woody. Lennoaceae differ because they lack fibrous cells (libriform fibers), lack rays within the vascular strands, and have markedly elliptical vessel-to-vessel pits without vestures. Lennoaceae have secondary xylem with short, wide vessel elements with thick walls, horizontally elongate elliptical pits, simple perforation plates much narrower than the vessel lumen; variously uneven vessel wall thickenings; and axial parenchyma. The wood of Lennoaceae shows resemblances to unrelated succulents such as \textit{Kalanchoe} (Crassulaceae) and \textit{Lithops} (Aizoaceae). The vessel features also suggest adaptation to high water tensions as root parasites in desert areas, whereas the lack of imperforate tracheary elements may relate to support of the underground stem portions by sand or rock detritus. Habit and ecology are more important in the architecture of lennoaceous xylem than systematic affinities. The four species of Lennoaceae differ from each other in minor xylary features.

URL:http://booksandjournals.brillonline.com/content/journals/10.1163/22941932-20170153
DOI:10.1163/22941932-20170153
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith