APIALES, NAKAI, 1930

Wheeler, Elisabeth A., Manchester, Steven R. & Baas, Pieter, 2023, A late Eocene wood assemblage from the Crooked River Basin, Oregon, USA, PaleoBios 40 (14), pp. 1-55 : 48-49

APIALES

Araliaceae Plerandreoxylon oskoslkii not found

? MALPIGHIALES

Salicaceae ? Unnamed not found

INCERTAE SEDIS

Theaceae ?, Hamamelidaceae ? Hamamelidoxylon sp. Hamamelidoxylon suzukii

a temperate association including Sequoia Endl. (1847) , Platanus , Quercus , Corylus L. (1753), Celtis , Zelkova Spach (1841) , and Tilia L. (1753). Comparing the Oligocene Gray Ranch woods with the older woods from Dietz Hill ( UF 278) and Post Hammer ( UF 279) sites also reflects changes in wood features correlated with change in paleoclimate; the Oligocene Celtis and Zelkova woods are distinctly ring-porous.

Locality UF 278 vs. UF 279

It is noteworthy that although the Post Hammer ( UF 279) and the Dietz Hill ( UF 278) localities are only 1.6 km apart ( Fig. 1C ) and believed to be of similar age they have few species in common, only Platanoxylon haydenii , Fagus dodgei , and Ulmus woodii ( Table 4). In fact, there are relatively few families in common: Pinaceae , Cupressaceae , Magnoliaceae , Lauraceae , Fabaceae , and Araliaceae were found at Dietz Hill and not at Post Hammer; conversely, Trochodendraceae Eichler (1865) , Cercidiphyllaceae Engl. (1907) , Cannabaceae , Anacardiaceae , and Malvaceae were found at Post Hammer and not at Dietz Hill. Juglandaceae and Sapindaceae were found at both localities, but the genera are different.

We consider it likely that these differences reflect lat- eral variation and different subenvironments. If we treat them collectively, the diversity increases, but the wood assemblage is still less diverse than the contemporaneous Teater Road compression flora some 11.5 km to the east ( Fig. 1C ). This compression flora is preserved in lacustrine shale and has about 51 genera of leaves and 57 of flowers, fruits, and seeds (Manchester and Lott, in progress). It includes only a few broadleaved evergreens ( Mahonia Nutt. (1818) , and perhaps Lauraceae ), and a variety of deciduous angiosperms including Ulmaceae ( Ulmus , Cedrelospermum Saporta emend. Manchester 1987), Fagaceae ( Quercus ), Betulaceae Gray, 1821 ( Carpinus L., 1753; Alnus Mill., 1754 ), Malvaceae ( Florissantia Manchester, 1992; Craigia W.W. Sm. and W.E. Evans, 1921 ), Sapindaceae ( Koelreuteria , Dipteronia , Acer spp. ), Simaroubaceae DC., 1811 ( Ailanthus Desf., 1786 ; Chaneya Wang and Manchester, 2000), Fabaceae ( Cercis and other genera), Rhamnaceae Juss., 1789 ( Paliurus Mill., 1754 ), and Hydrangeaceae Dumort., 1829 ( Hydrangea L., 1753).

Our understanding of the composition of Dietz Hill ( UF 278) vegetation comes from silicified fruits and seeds as well as woods from the same site. Disseminules that co-occur with the Dietz Hill woods include Magnolia , Menispermaceae Juss. (1789) , Meliosma Blume (1823) , Sabia Colebr. (1819) , Platanaceae , Ampelopsis A.Rich. ex Michx. (1803) , Aphananthe , Carya , Burseraceae , Cedrela , Rutaceae , Acer , and Alangium Lam. (1783) , as illustrated and described by Manchester and McIntosh (2007). Other fruits that have been identified subsequently from the same site (Manchester personal observation) include Hydrangea and Juglans . Once again, this shows the importance of utilizing multiple plant parts to gain a fuller picture of the taxonomic composition, as was also the case for the Clarno nut beds flora. The extent of overlap between the wood and fruit genera at Dietz Hill ( Magnolia , Carya ) is minimal. Some of the fruits and seeds may represent non-arborescent taxa that would not be expected among the woods( Ampelopsis , Menispermaceae , Hydrangea ), but most of the other disseminules likely represent trees.

Figures

Figure 1. A. Oblique northerly view of Dietz Hill, site UF278. White tuff capping the hill yielded radiometric age of 36.21±0.26 Ma (n=26) (Manchester and McIntosh 2007). Woods and fruits and seeds derive from the same tuff. Google Earth imagery. B. Index map of Oregon. Yellow rectangle showing the location of satellite image in C. C. Paleobotanical localities in the vicinity of Post, Oregon, in the Crooked River valley. Yellow line marks the approximate contact between the Clarno Formation (Tc) and overlying John Day Formation (Tjd) based on the geologic mapping of Waters (1968). Quaternary deposits in the Crooked River floodplain and localized Plio-Pleistocene igneous intrusions not shown (see Waters 1968 for detail). Late Eocene localities: UF279 Post Hammer site; UF278 Dietz Hill (subject of this treatment), UF254 Brummers Spring, UF256 Teater Road leaf locality. Early Oligocene locality: UF258. Crooked River leaf site (Chaney 1927, Meyer and Manchester 1997).