Cupressinoxylon sp.

Iamandei, Stanila, Iamandei, Eugenia, Codrea, Vlad Aurel & Fărcaș, Cristina, 2024, A New Mid-Miocene Wood From Ocna Dej Salt Mine, Acta Palaeontologica Romaniae 20 (2), pp. 25-32 : 27

Cupressinoxylon sp. aff. Thujoxylon sp.

Fig. 2 , a-i.

Studied material. We had in study a sample of charred wood that showed a cupressaceous structure. It was collected from the area of Ocna Dej salt deposit of Middle Badenian age (Wielician). The sample is stored in PSM.UBB, under PR no. 835.

Microscopic description. Growth rings – appear in cross section relatively wide, showing a gradual diminution of the tracheids, to the late wood, so the growth rings boundaries could be guessed as marked by the final wood with compressed small and thick-walled cells, suddenly followed by the early-wood which starts with larger cells. Axial canals not present.

The tracheids – are quite thick-walled and have a polygonal shape with rounded corners in cross section, sometimes deformed by compression. In the early wood, their radial/tangential diameter is of 13–18(20) / 13– 17(18) μm, and are thick- walled. The wall thickness is of 8-12 μm the double wall. To the late wood the cells size gradually decrease toward the final 3-5(-9) rows of final wood smaller tracheids, of 5-7(-12) / 8-15 μm in diameter and thick walled, of 12-16 μm the double wall. In cross section the cells appear regularly distributed in 1-8-12 radial rows, or more, between two successive rays. Their density is of 900-1100 tracheids per mm 2. On the radial walls, the pits appear, usually, in uniseriate arrangement. The pits are round, of bordered type, with 7-10 μm in diameter, with a round to elliptic aperture. On the tangential walls the pitting is absent or rarely appear as smaller pits, of 5-7 mm, uniseriately arranged, but usually is difficult to see due to bad preservation. Helical thickenings, crassulae, callitroid thickenings - absent. Organic deposits, usually, absent.

Axial parenchyma – is present as few cells, in diffuse arrangement, scattered among tracheids or in short lines and, usually, are full of dark resin content. In vertical view the string of rectangular parenchyma cells, probably have nodular transverse end walls, difficult to observe, due to poor preservation.

Rays – appear thin and linear in cross section and, in tangential view, appear as exclusively uniseriate, are low to medium tall, of 3-15 cells, or more. Ray density is 3- 7(-9) rays per tangential mm. Regarding the composition, the rays are homogeneous, composed by parenchymatous ray cells all procumbent, the marginals slightly taller. Ray tracheids are not present. The ending walls of ray cells are smooth and the horizontal walls are smooth and pitted, details usually, poorly preserved. Indentures not visible, or absent. Cross fields with small cupressoid pits of 3-5(7) mm in diameter, as rows of 1-3 pits with inclined slit-like apertures, sometimes in 2-3 superposed rows alternately arranged.

Resin canals – axial or radial - absent. Mineral inclusions – (as crystals) not present.

Figures

Fig. 2. Cupressinoxylon sp. aff. Thujoxylon sp. Specimen PSM, UBB - PR no. 835. a, b, c – cross-section: growth rings variably sized, with gradual transition from early to latewood, parenchyma few, diffuse, resin ducts absent. d, e, f – tangential section: rays uniseriate, poorly preserved structure. g, h, i – radial section: uniseriate tracheidal pitting, rays homocellular, with poorly preserved cross-fields with 1-3 cupressoid pits.