A Diverse Assemblage Of Late Eocene Woods From Oregon, Western Usa
Author
Wheeler, Elisabeth A.
Author
Manchester, Steven R.
text
Fossil Imprint
2021
2022-02-18
77
2
299
329
http://dx.doi.org/10.37520/fi.2021.022
journal article
10.37520/fi.2021.022
2533-4069
7167583
Fagus dodgei
sp. nov.
Text-fig. 4a–h
H o l o t y p e. Designated here. UF 279-34468 (Textfig. 4a, b, d–h). Minimum estimated axis diameter
10 cm
.
A d d i t i o n a l m a t e r i a l. UF 279-30165 (Textfig. 4c).
P l a n t F o s s i l N a m e s R e g i s t r y N u m b e r.
PFN 002679 (for new species).
Text-fig. 4.
Fagus dodgei
sp. nov.
, a, b, d–h: UF 279-34468; c: UF 279-30165. a:
Wood
diffuse-porous to semi-ring-porous with distinct latewood zone with narrower vessels; vessels solitary and in short multiples; diffuse, diffuse-in-aggregates axial parenchyma visible in latewood, TS. b: Growth ring boundary, TS. c: Opposite intervessel pitting, TLS. d: Scalariform perforation plate with fewer than 10 bars, RLS. e: Simple perforation plates (PP), RLS. f: Vessel-ray parenchyma pitting with reduced borders and frequently oval in outline, RLS. g: Rays 1–4(–5)-seriate with variable numbers of marginal rows, TLS. h: Rays of two distinct sizes, widest rays>10-seriate, TLS. Scale bars: 200 µm in a, h; 100 µm in b, e, g; 50 µm in d, f.
R
e p o s i t o r y.
Paleobotany Collections
,
Florida
Museum of Natural History
, Gainesville,
Florida
,
USA
.
E t y m o l o g y. Named for William W. Dodge IV, who made sure paleoxylotomy in
North Carolina
was alive and well during the Covid-19 pandemic.
T y p e l o c a l i t y. UF 279. About
3 km
east of Post,
Crook County,
Oregon
,
USA
.
T y p e s t r a t u m a n d a g e. John Day Formation,
Eocene.
D i a g n o s i s. Growth rings distinct. Diffuse-porous to semi-ring-porous. Vessels mostly solitary, but also in occasional radial, oblique, or tangential pairs; tangential diameters average <100 µm; perforations simple and scalariform; intervessel pits opposite, transitional to scalariform; pits to ray parenchyma oval to horizontally elongate, with reduced borders. Non-septate fibers with distinctly bordered pits on radial walls. Axial parenchyma diffuse and diffuse-in-aggregates as short uniseriate bands. Rays uniseriate and multiseriate, tending to be of two sizes, wider multiseriate rays>10-seriate; wide rays irregularly spaced; average multiseriate ray height>
1 mm
; homocellular to heterocellular, body composed of procumbent cells with marginal rows of square and upright cells. Solitary rhomboidal crystals occasional in procumbent ray cells. Storied structure absent.
D e s c r i p t i o n. Growth rings distinct, marked by radially narrow fibers, and differences between latewood and earlywood vessels of subsequent rings (latewood vessels are narrower and not as crowded as earlywood vessels) (Textfig. 4a, b). Diffuse-porous to semi-ring-porous (
Text-fig. 4a
).
Vessels mostly solitary, but also occasional radial, oblique and tangential pairs; average earlywood tangential diameter 55 (11), range 39–79 µm; vessel frequency in first half of growth ring ca. 90/mm
2
; perforations simple and scalariform with 4-24 bars, mostly 8–12 bars (Textfig. 4d, e); intervessel pits opposite (5–7 µm), transitional to scalariform (
Text-fig. 4c
); pits to ray parenchyma oval to horizontally elongate, with reduced borders (
Text-fig. 4f
); vessel element lengths 450–520 µm.
Non-septate fibers with distinctly bordered pits on radial walls.
Axial parenchyma apotracheal, diffuse as isolated cells and diffuse-in-aggregates as short uniseriate bands, more easily seen in latewood (
Text-fig. 4a
).
Rays uniseriate and multiseriate, tending to be of two sizes, with rays 1–5(–6)-seriate common, and wider multiseriate rays to 18–20-seriate, with few intermediate widths; wide rays irregularly spaced (
Text-fig.
4g
, h
); average multiseriate ray height
1.56 mm
, range
0.74–2.69 mm
; homocellular to heterocellular, body composed of procumbent cells usually with 1–4 (up to 8) marginal rows of square and upright cells.
Solitary rhomboidal crystals occasional in procumbent ray cells. Storied structure absent.
C o m p a r i s o n s w i t h e x t a n t w o o d s. The following combination of features indicates affinities with
Fagus
(Fagaceae)
: distinct growth rings (1p), simple and scalariform perforation plates (13p 14p), opposite intervessel pitting (21p), vessel-ray parenchyma pits with reduced borders (30a), narrow numerous vessels (42a 43a 46a 47a), non-septate fibers with distinctly bordered pits on radial walls (62p 66p), diffuse and diffuse-in-aggregates axial parenchyma (76p 77p), wide rays>10 cells wide and>
1 mm
high (99p 102p). To the best of our knowledge, there is not a reliable means of distinguishing present-day
Fagus
species
based on wood anatomy alone (
Brazier and Franklin 1961
,
Wheeler and Dillhoff 2009
).
Woods of the
Platanaceae
are common in the Paleogene of the western
USA
. and superficially resemble
Fagus
. However, there are features useful in distinguishing them (e.g.,
Panshin and DeZeeuw 1980
,
Hoadley 1990
).
Fagus
consistently has vessel-ray parenchyma pits with reduced borders that are somewhat horizontally elongate, while
Platanus
L. has vessel-ray parenchyma pits similar to intervessel pits. Vessel multiples are rare in both, but
Platanus
has some tangential multiples and a tendency to vessels being tangentially arranged; consequently, intervessel pits are more common in
Platanus
than in
Fagus
. Intervessel pits are consistently opposite in
Platanus
;
while
Fagus
usually has transitional (opposite- scalariform) intervessel pitting. Spacing of and size of the wide rays is more uniform in
Platanus
than in
Fagus
. All these features can be reviewed in the InsideWood image collection (InsideWood 2004-onwards).
C o m p a r i s o n s w i t h f o s s i l w o o d s.
Fagus
- like woods have been described as species of
Fagus
,
Fagoxylon
STOPES
et fUJII, and
Fegonium
UNGER (
Süss 1986
)
. Descriptions of most lack details that would permit confirming their relationships with
Fagus
. There are at least ten
Fagus
-like woods reported from the Mio-Pliocene of Europe (
Gregory et al. 2009
), but their descriptions are brief, so it is not possible to do detailed comparisons of them with this late Eocene wood.
There are differences between
Fagus dodgei
and the midMiocene
Fagus manosii
E.A.WHEELER
et T.A.DILLHOff from
Washington State
,
USA
(
Wheeler and Dillhoff 2009
), which had more scalariform intervessel pits and larger opposite intervessel pits, narrower and shorter rays (to 16-seriate and
1.7 mm
high), less axial parenchyma, and lacked crystals. Thus, although there is no reliable way to distinguish between extant species of
Fagus
, we are choosing to recognize
Fagus dodgei
as a new species to emphasize that it differs from the mid-Miocene Vantage
Fagus
wood.
R e m a r k s.
Denk and Grimm (2009)
proposed that
Fagus
evolved in the Northern Pacific Region. Fossil species of
Fagus
, based on fruits and leaves, are known from the Paleogene of the Pacific Northwest. The middle Eocene
Fagus langevinii
MANCHESTER
et R.M.DILLHOff from McAbee,
British Columbia
, and Republic,
Washington
, differs from the early Oligocene
Fagus pacifica
R.W.CHANEY
from the Bridge Creek flora of
Oregon
(
Manchester
and Dillhoff 2004
).
C o - o c c u r r i n g f r u i t s. A single silicified
Fagus
nut was recovered from the same locality, UF 279 (
Manchester
and McIntosh 2007
).