Platanoxylon cf. haydenii

Wheeler, Elisabeth A. & Manchester, Steven R., 2021, A Diverse Assemblage Of Late Eocene Woods From Oregon, Western Usa, Fossil Imprint 77 (2), pp. 299-329 : 320

Platanoxylon cf. haydenii (fELIX) SÜSS et MÜLL.-STOLL, 1977

Text-fig. 10a–h

M a t e r i a l. UF279-34469; UF 279-34470, minimum estimated axis diameter 30 cm.

D e s c r i p t i o n. Growth rings present, marked by slightly noded rays and 1–2 rows of radially narrow fibers. Wood diffuse-porous.

Vessels solitary and in short multiples, some tangentially arranged ( Text-fig. 10a, b ); average tangential diameter 76 (11) µm, range 59–96 µm; average 45/mm 2. Perforation plates exclusively scalariform, generally with fewer than 20 bars ( Text-fig. 10c, d ); intervessel pits opposite (Textfig. 10f, g), vessel-ray parenchyma pits not observed.

Fibers non-septate, pits not observed.

Axial parenchyma diffuse-in-aggregates, in interrupted short uniseriate lines ( Text-fig. 10a, b, f ).

Rays of two distinct sizes, larger rays often>20 cells wide ( Text-fig. 10a, b, h ), composed of procumbent cells, sometimes with 1–2 marginal rows of square cells; multiseriate ray height averages 3.05 mm, range 1.1– 5.53 mm.

R e m a r k s. Although vessel-ray parenchyma pits were not observed in these samples, their other characteristics indicate they are Platanoxylon (narrow numerous vessels, some in tangential multiples ( Text-fig. 10a, b ); scalariform perforation plates ( Text-fig. 10c, d, e ); opposite intervessel pits ( Text-fig. 10f, g ); diffuse-in-aggregates parenchyma; tall and wide rays composed mostly of procumbent cells ( Text-fig. 10h ). The characteristics that distinguish them from other woods with wide rays (e.g., Fagus and Euptelea ) were detailed by Scott and Wheeler (1982) and discussed earlier with reference to Fagus dodgei . Platanoid woods are common in the Paleogene of western North America. Woods similar to Platanoxylon haydenii are common in the older Clarno Formation, with multiple samples occurring at both the Nut Beds ( Wheeler and Manchester 2002) and Hancock Canyon ( Wheeler and Manchester 2014). These Post Hammer woods with their exclusively scalariform perforation plates are similar to other Eocene platanoid woods and differ from present-day Platanus woods that have both simple and scalariform perforation plates.

Figures

Text-fig. 10. Platanoxylon cf. haydenii, a, e, h: UF 279-34470; b, c, d, f g: UF 279-34469. a, b: Diffuse porous wood with vessels solitary and in small multiples, which are mostly tangential or oblique, diffuse and diffuse-in-aggregates axial parenchyma., TS. c–e: Scalariform perforation plates. f, g: Opposite intervessel pits, TLS. h: Two size classes of rays, TLS. Platanus sp., UF 279- 24552. i: Predominantly solitary vessels, diffuse and diffuse-in-aggregates parenchyma, growth ring boundary distinct, noded rays, TS. j: Simple perforation plates (PP), RLS. k: Body of ray with procumbent ray cells, RLS. l: Scalariform perforation plate, RLS. m: Rays of two sizes, wide rays>10-seriate, TLS. Scale bars: 200 µm in a, b, h, i, m; 100 µm in j, k: 50 µm in c, d, e, f, l.