A REEXAMINATION OF CONIFER DIVERSITY IN THE REPUBLIC FLORA

Conifers are well known as a significant component of the late early Eocene Republic flora of northeastern Washington State. Among the most commonly collected specimens are members of Pinaceae (Pinus, Picea, Pseudolarix, and Abies); Cupressaceae (Metasequoia, Sequoia) and Cephalotaxaceae. While some of these taxa are well established there are others that have more tentative identifications that limit our ability to accurately assess the diversity of the flora. An understanding of this diversity is critical to studies that use the Republic flora as an established reference point. The first formal taxonomic descriptions are those of Berry (1929) who named three species for Pinus needles and one for winged seeds. Abies milleri was established by Schorn and Wehr (1986) on the basis of cone scales, seeds, twigs bearing foliage and isolated stems and leaves. These same authors later cited Republic as having the oldest verifiable megafossil record of spruce (Picea), fir (Abies) and hemlock (Tsuga, Wehr and Schorn 1992). Also in 1992, two species of Pseudolarix were named, one from Republic and the other from Princeton (Gooch, 1992). The widespread compression taxon Metasquoia occidentalis is the most common fossil at Republic. In addition to these formally described taxa, other tentative identifications have been offered. Within Cupressaceae these include Taiwania, Cryptomeria, Cunninghamia; the cupressoid Chamaecyparis, Thuja, Thujopsis and Mesocyparis and the taxodiod Sequoia and Glyptostrobus. Needles of Cephalotaxaceae (Amentotaxus, Cephalotaxus and/or Torreya), and those referred to Sciatopitys are also found. A taxonomic assessment of the Republic conifers will not only provide data useful for examining the evolutionary and distributional history of conifer lineages, but will also provide an additional data source to augment paleoclimate estimates based on angiosperm leaf morphotypes.