Hamamelidoxylon crystalliferum, Wheeler & Manchester, 2021

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 : 312-314

Hamamelidoxylon crystalliferum sp. nov.

Text-fig. 7a–i

H o l o t y p e. Designated here. UF 279-34464 (Textfig. 7a–i). Minimum estimated axis diameter 15 cm.

P a r a t y p e. UF 279-24555 (minimum estimated diameter 30 cm).

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.

PFN002681 (for new species).

R e p o s i t o r y. Paleobotany Collections , Florida Museum of Natural History , Gainesville, Florida, USA .

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.

E t y m o l o g y. Named for crystals in this wood.

D i a g n o s i s. Growth rings distinct to indistinct. Wood diffuse-porous. Vessels predominantly solitary, narrow, and numerous. Perforation plates exclusively scalariform, fewer than 20 bars per perforation plate. Intervessel pitting scalariform. Vessel-ray parenchyma pits with reduced borders and horizontally elongate. Fibers non-septate, with bordered pits on radial walls. Axial parenchyma rare. Heterocellular rays, 1–2 cells wide. Solitary prismatic crystals in chambered and non-chambered square to upright ray cells, crystal-containing cells somewhat inflated.

D e s c r i p t i o n. Growth rings boundaries distinct to indistinct, marked by a few rows of radially narrow fibers, with latest latewood vessels narrower than the first earlywood vessels ( Text-fig. 7a, b ). Wood diffuse-porous.

Vessels predominantly solitary, angular in outline (Textfig. 7a, b), mean tangential diameter 43 (8)–47(6); 104– 149 mm 2; perforations all scalariform, 11–15 bars (Textfig. 7e); intervessel pits scalariform ( Text-fig. 7c ); vessel-ray parenchyma pits horizontally elongated ( Text-fig. 7f ), vessel element lengths 690–950 µm.

Fibers non-septate, medium-thick to thick walled; distinctly bordered pits on radial walls and tangential walls ( Text-fig. 7c, f ).

Axial parenchyma rare.

Rays 1–2(–3)-seriate, heterocellular, uniseriate and biseriate portions occasionally alternating, but not commonly ( Text-fig. 7f, g ); width of uniseriate portions usually not the same as the biseriate portions; uniseriate rays composed of upright cells, biseriate portions of rays composed of procumbent cells, with uniseriate portions of 1–4 (or more) rows of upright cells, upright cells at least 4× higher than the procumbent cells ( Text-fig. 7h ).

Solitary crystals occasional in chambered (2–3) upright ray cells, crystalliferous cells usually inflated ( Text-fig. 7i ).

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. In InsideWood, the combination of diffuse-porous woods (5p), narrow, numerous vessels (42a 43a 47a 48a) that are predominantly solitary (9p), exclusively scalariform perforation plates (13a 14p), scalariform intervessel pits (20p), vessel-ray parenchyma pits horizontally elongate with reduced borders (32p), axial parenchyma rare (75p), fibers with distinctly bordered pits (62p), heterocellular 1–2-seriate rays (97p 104a 105a), and crystals in chambered upright ray cells (140p) is unique to the Hamamelidaceae , occurring in Corylopsis , Eustigma GARDNER et CHAMP. , Sinowilsonia HEMSL. (subfamily Hamamelidoidieae ), and Mytilaria LECOMTE (subfamily Mytilariodeae ). Of these, Sinowilsonia is the most similar because of its lower number of bars per perforation plate (<20) compared to the three other genera.

The anatomy of extant Hamamelidaceae has been reviewed by Tang (1943), Skvortsova (1975), and Wheeler et al. (2010). The growth ring boundaries resemble those seen in evergreen Asian species of the family (e.g., Chunia H.T.CHANG , Exbucklandia R.W.BR. ) more than those of deciduous species.

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. Lignier’s (1907) diagnosis of the genus Hamamelidoxylon includes these features: rays numerous, rays uniseriate, rarely biseriate, vessels predominantly solitary, scalariform perforation plates, axial parenchyma rare. His plate XX (line drawings of H. renaulti LIGN. ) shows a perforation plate with over 25 bars, horizontally elongate vessel-ray parenchyma pitting, ray cell walls with abundant pitting as seen in radial sections, and thick-walled fibers. Subsequently, woods with rays 1–2(–3) cells wide were assigned to the genus, e.g., the European species: H. castellanense GRAMBAST- fESSARD (GrambastFessard 1969), H. daphniphylloides H.GOTTWALD ( Gottwald 1992) , and H. rhenamum BURGH ( van der Burgh 1973). The genus has been used for woods that have characteristics of the family, but not necessarily of the genus Hamamelis L.

Three species of Hamamelidoxylon have been described from the Pacific Northwest of NorthAmerica: H. uniseriatum E.A.WHEELER et MANCHESTER from the middle Eocene Clarno Formation ( Wheeler and Manchester 2002, 2014) whose characteristics best fit the Tribe Exbucklandiodeae , and H. beckii E.A.WHEELER et T.A.DILLHOff and H. suzukii E.A.WHEELER et T.A.DILLHOff from the middle Miocene Vantage Forests, Washington ( Wheeler and Dillhoff 2009). Table 2 compares H. crystalliferum to them and to the European and Asian Hamamelidoxylon species that have reasonably complete descriptions. The data in the table show that H. crystalliferum ’s combination of 15 or fewer bars per perforation plate, rays 1–2(–3) cells wide, and crystals in

1. Takahashi and Suzuki (2003), 2. Wheeler and Manchester (2002), 3. Wheeler and Manchester (2007), 4. Gottwald (1992), 5. Lignier (1907), 6. Crawley (2001), 7. Wheeler and Dillhoff (2009), 8. van der Burgh (1973), 9. Grambast–Fessard (1969)

chambered upright ray cells does not match any of the other species and indicates it is appropriate to create a new species.

Liquidambaroxylon and all Altingiaceae never possess crystals in chambered upright ray cells.

C o - o c c u r r i n g f r u i t s / s e e d s. The fossil genus Fortunearites MANCHESTER, known from infructescence in the middle Eocene Clarno Nut Beds, Oregon, has a combination of characters found only in Fortunearia and Sinowilsonia (Manchester 1994, Manchester et al. 2009). It is possible that these two late Eocene wood samples might be related to the plant that produced Fortunearites . However, present-day Fortunearia wood has banded axial parenchyma, so is distinct from Sinowilsonia and these Post Hammer woods.

Figures

Text-fig. 7. Hamamelidoxylon crystalliferum sp. nov., UF 279-34464. a: Diffuse porous wood with exclusively solitary vessels, tending to be angular in outline, TS. b: Growth ring boundary, marked by radially narrowed fibers, latewood vessels narrower than earlywood vessels of the next ring, fibers thick-walled, no axial parenchyma visible, TS. c: Scalariform intervessel pits in narrow vessel (left), fibers with distinctly bordered pits, TLS. d: Scalariform perforation plate, tyloses (T) formation from marginal ray cell, TLS. e: Scalariform perforation plates with fewer than 15 bars (PP), RLS. f: Vessel-ray parenchyma pits with