Bryological and Lichenological Section/ABLS
Crandall-Stotler, Barbara J. , Millar, Katherine .
Anatomical Studies of Verdoornia succulenta R. M. Schust. (Makinoaceae Nakai, Marchantiophyta) and a Re-evaluation of its Systematic Affinities.
The monotypic simple thalloid liverwort Verdoornia is a rare, poorly known, endemic of New Zealand. Named by Schuster in 1963 (J. Hattori Bot. Lab. 26: 261), V. succulenta was postulated to be a phylogenetically isolated taxon, with remote affinities only to Pellia or Makinoa. Characters that presumably are unique to the genus include neckless archegonia that occur in scattered clusters on the dorsal surface of the thallus and clavate ventral slime papillae that enrobe the ventral surface in mucilage. In our molecular phylogenetic studies of the simple thalloid liverworts, Verdoornia is resolved as a sister taxon to the other genera of the Aneuraceae, a family that has been traditionally considered a crown group of the simple thalloids. Using a combination of paraffin-sectioning and SEM methods, we have investigated apical organization, gametangial development and morphology, and sporophyte anatomy of Verdoornia and representative taxa of the Aneuraceae. As in other elements of the Aneuraceae, Verdoorna possesses a large, lenticular apical cell, which is ventrally tilted, and stalked slime cells that arise only on the ventral surface of the thallus. The gynoecium, with its neckless archegonia and scattered scales, is exactly like that found in Aneura, except for its position on the dorsal surface of the main axis rather than a short lateral branch. Sporophyte anatomy is consistent with that of other taxa of the Aneuraceae. These findings are consistent with the molecular alignment of Verdoornia with Aneura and support the transfer of Verdoornia from the Makinoaceae (Pallaviciniineae) to the Aneuraceae (Metzgeriineae).
1 - Southern Illinois University, Department of Plant Biology, 1125 Lincoln Drive, Carbondale, Illinois, 62901-6509, USA
apical cell geometry
Presentation Type: Paper
Location: Ballroom 3 (Cliff Lodge)
Date: Monday, August 2nd, 2004
Time: 4:30 PM