Woods of the Eocene Nut Beds Flora, Clarno Formation, Oregon, USA

Woods of the Eocene Nut Beds Flora, Clarno Formation, Oregon, USA. E. A. Wheeler and S. R. Manchester. 2002. IAWA Journal, Supplement 3, 188 p.

The middle Eocene age Clarno Nut Beds Flora in north-central Oregon is one of the most significant fossil plant assemblages in the northern hemisphere, with abundant and diverse, often exquisitely preserved, fossil fruits, seeds, leaves, and woods. There are few other fossil plant assemblages that can compare to the Nut Beds in taxonomic diversity, quality of preservation, and sheer beauty of the fossils. The Nut Beds assemblage is unusual in that it contains fossil leaves in addition to silicified fossil woods and three dimensionally preserved fruits and seeds. As such, the Nut Beds Flora is a benchmark assemblage against which all other Eocene floras may be compared. Fortunately for us, comparisons are greatly facilitated by two meticulously prepared monographs: the fruits and seeds of the Nut Beds Flora were treated in detail by Manchester (1994) and now the fossil woods have been monographed by Wheeler and Manchester (2002). Taxon descriptions are carefully and clearly written and the fossils are thoroughly illustrated. Every paleobotanist working in the Cretaceous or Tertiary will want to have copies of these monographs available for reference.

The assemblage of fossil woods in the Nut Beds Flora is the most diverse ever described from a single locality. Wheeler and Manchester examined over 600 specimens of silicified woods and recognized 66 genera and 76 species from this locality. In addition to their obvious utility in documenting the taxonomic composition of the Clarno flora, this fossil wood assemblage is a valuable resource that can be used to estimate paleoclimatic parameters for the middle Eocene of central Oregon. Together with the fruit and seed assemblage these fossils can be used in evaluating biogeographic relationships and other aspects of paleobiology and history.

In this publication Wheeler and Manchester provide detailed descriptions and illustrations of all fossil wood types in the Clarno Net Beds Flora. Several tables are provided that summarize the anatomical characteristics and taxonomic composition of the assemblage. Many of the taxa are assigned to genus and species, but others are assigned to families or orders, and some are simply assigned to "xylotypes" and are not given formal taxonomic names. The taxonomy and nomenclature of fossil woods is extremely complicated and cluttered with dubious names and the authors of this work have taken the pragmatic approach of using xylotypes (major wood anatomical categories) for woods of unknown affinities. Some people might view this as a fault of this publication, but in my opinion the use of xylotypes for some woods was clearly appropriate.

This volume represents years of work by two of the world's leading paleoxylotomists. The descriptions are of a consistent format and the illustrations are of the usual high quality we have come to expect from these authors. I found one case where larger, higher magnification images would have shown the anatomical features more clearly (e.g., fig. 17), but this is the best I can do in the way of criticisms. The volume is well made and reasonably priced, and I highly recommend it.

REFERENCES

MANCHESTER, S. R. 1994. Fruits and seeds of the middle Eocene Nut Beds Flora, Clarno Formation, Oregon. Palaeontographica Americana, 58:1-205.

PATRICK S. HERENDEEN

Department of Biological Sciences

The George Washington University

Washington DC 20052

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