Cupressinoxylon canadense ( Schroeter, 1880 ) Kraeusel, 1949

Kłusek, Marzena, 2014, Miocene coniferous woods of the Polish Carpathian Foredeep, Acta Palaeontologica Polonica 59 (3), pp. 697-708 : 701-703

Cupressinoxylon canadense ( Schroeter, 1880) Kraeusel, 1949

Fig. 5A–F .

1880 Sequoia canadensis Schroeter, 1880 ; Schroeter 1880: 17, pl. 2: 11–21; pl. 3: 22–26.

1913 Sequoia wellingtonioides Prill, 1913 ; Prill 1913: 48.

1919 Cupressinoxylon wellingtonioides ( Prill, 1913) Kraeusel, 1919 ; Prill and Kraeusel 1919: 293, pl. 22: 7, 8.

1949 Cupressinoxylon canadense ( Schroeter, 1880) Kraeusel, 1949 ; Kraeusel 1949: 175.

Material.—One coalified fragment of wood, about 10 cm long, sourced from Hebdów locality and marked as MZ LXXII ( Fig. 5A–F ).

Description.—The specimen comprises the part of the branch. Growth rings are narrow, with thin latewood lay- er ( Fig. 5A ). Axial parenchyma appears sparse. Transverse walls of parenchyma cells are smooth or sometimes with dentate thickenings ( Fig. 5F ).

Tracheids have angular shape and thin walls. On radial walls of tracheids occur uniseriate or biseriate bordered pits, 8.5–13 μm in diameter, arranged in opposite, continuous rows. Pits are circular or sometimes slightly compressed along the sides of contact. Pit apertures are also circular in earlywood or slit-like, obliquely oriented in latewood ( Fig. 5C ). Bars of Sanio occur frequently. Tangential walls of tracheids have bordered pits arranged in a single irregular, scattered row ( Fig. 5D ). Pits possess circular shape (8.5–10.5 μm in diameter) and slit-like, oblique apertures.

Rays are uniseriate or sometimes partially biseriate, 2–45 cells high ( Fig. 5E ). They are composed of oval or rectangular cells. Rays have thin and smooth, sporadically pitted transverse walls and smooth tangential walls with no indentures. Cross-field pits, 8–9 μm in diameter, in median cells form a single row, then 1–3 pits appear per field. In marginal cells, occur usually 2–6 pits organised in two rows ( Fig. 5B ). Pits have circular or oval outlines. Pit apertures are obliquely oriented in earlywood and latewood. Ray parenchyma often includes resinous contents. Ray tracheids occur rarely.

Remarks.—The described features of wood anatomical structure, especially the absence of resin canals, character of cross-field pitting and bordered pits on the walls of tracheids, indicate the affiliation of the examined specimen to Cupressinoxylon canadense ( Schroeter, 1880) Kraeusel, 1949 . Cupressinoxylon canadens e was established by Kraeusel (1949) on the basis of previously defined taxa. This name referred to Sequoia canadensis originating from Miocene of North Canada ( Schroeter 1880). Kraeusel (1949) interpret- ed as Cupressinoxylon canadense also Miocene wood from Opole ( Poland). The taxonomical position of this wood was revised many times. It had been initially attributed to Sequoia wellingtoniides Prill, 1913 later re-classified to Cupressinoxylon wellingtonioides ( Prill, 1913) Kraeusel, 1919 ( Prill and Kraeusel 1919) and finally determined as Cupressinoxylon canadense ( Kraeusel 1949) . Taking into consideration living trees, analysed wood is most similar to the wood known from Glyptostrobus Endlicher, 1847 , Metasequoia Hu and Cheng, 1948 , Taxodium Richard, 1810 , and Sequoia Endlicher, 1847 . Among the mentioned genera, Glyptostrobus wood differs from the examined specimen in the presence of glyptostroboid cross-field pitting, nodular transverse walls of wood parenchyma cells and the absence of ray tracheids. The rays are homogeneous also in Metasequoia and Taxodium wood. The wood of Metasequoia , Taxodium , and Sequoia , in distinction from the analysed specimen, possess taxodioid pits in the cross field. Moreover, the genus Taxodium is marked by the presence of conspicuous thickenings of transverse walls of axial parenchyma cells and occasionally up to triseriate bordered pits on radial walls of tracheids (Henry and Mc Intyre 1926; Visscher and Jagels 2003). The anatomical structure of the analysed specimen is, in turn, consistent with giant sequoia wood ( Sequoiadendron giganteum [Lindley, 1853] Buchholz, 1939). This species is characterised by the presence of cupressoid pits in the cross field. In fossil wood taxonomy, giant sequoia corresponds to Cupressinoxylon canadense species ( Prill and Kraeusel 1919; Kraeusel 1949). This fact confirms above established classification.

Stratigraphic and geographic range.— Tertiary; Europe, North America.

Figures

Fig. 5. Microphotographs of fossil wood Cupressinoxylon canadense (Schroeter, 1880) Kraeusel, 1949 from Hebdów, Middle Miocene; specimen MZ LXXII. A. Narrow growth rings (TS). B. Crossfield pitting (RLS). C. Bordered pits on radial walls of tracheids (RLS). D. Tangential walls of tracheids with bordered pits (arrow) (TLS). E. Tall, uniseriate rays (TLS). F. Horizontal walls of parenchyma cells with dentate thickenings (arrow) (TLS). Scale bars 50 μm.