FARRAR, DONALD R.*, CINDY L. JOHNSON-GROH, AND WARREN D. HAUK. Department of Botany, Iowa State University, Ames, IA 50011; Department of Biology, Gustavus-Adolphus College, St. Peter, MN 56082; Department of Biology, Denison University, Granville, OH 43023. - Biology and conservation of the Ophioglossaceae-A tribute to Warren "Herb" Wagner.The Ophioglossaceae possess a suite of characters that long ago
prompted speculation on their possible descent from Paleozoic
Coenopterid ferns. The combination of vascular cambium
(Botrychium), collateral vascular bundles, non-circinnate
vernation, single annual leaf cleft into fertile and sterile segments,
underground apex with preformed leaves, simple, fleshy, hairless
mycorrhizal roots and long-lived subterranean gametophytes suggest a
lineage separate from the remainder of ferns. Many of these plants
possess remarkably low intraspecific genetic diversity, perhaps due to
underground fertilization, and perhaps allowed by their mycorrhizal
relationship. Despite low genetic variability, Botrychium
species appear to have undergone recent and continuing speciation.
Aspects of Ophioglossaceae morphology, phytogeography, speciation, and
systematic relationships will be presented in the first half of the
symposium. Ecology and conservation issues will be presented in the
second half. Subtle species differences in morphology, combined with
small size, irregular appearance above ground, and rarity of many of
the species, present daunting challenges in conservation management.
Spore germination, gametophyte growth, fertilization and juvenile
sporophyte stages occur below ground. Current analyses of critical
underground stages are increasing our understanding of population
dynamics in Botrychium. Reviews of Ophioglossaceae floristics
and conservation needs in North America conclude the symposium.
Key words: Botrychium, conservation biology, Ophioglossaceae, Ophioglossum