Tetraclinis salicornioides (UNGER) KVAČEK

Dedicated in memory of the late FrantiŠek Holý (1935 - 1984), an eminent Czech palaeobotanist, Holý, František, Kvaček, Zlatko & Teodoridis, Vasilis, 2012, A Review Of The Early Miocene Mastixioid Flora Of The Kristina Mine At Hrádek Nad Nisou In North Bohemia (The Czech Republic), Acta Musei Nationalis Pragae Series B 68 (3 - 4), pp. 53-118 : 58

Tetraclinis salicornioides (UNGER) KVAČEK

Pl. 1, fig. 6, pl. 4, fig. 12, pl. 10, fig. 6

1847 Thuites salicornioides UNGER , p. 11, pl. 2, figs 1-4, pl. 20, fig. 8 (Radoboj).

1977a Tetraclinis sp. ; Holý, p. 111 (Hrádek/N., Kristina Mine).

1989 Tetraclinis salicornioides (UNGER) KVAČEK , p. 48, pl. 1, fig. 11, pl. 2, figs 2-14, pl. 3, figs 1-4, text-fig. 1 (Hrádek/N., Kristina Mine and many other sites, full synonymy).

Isolated cladode-like branch segments, up to 10 mm long, 2–5 mm wide, corresponding to pseudo-whorls, composed of pairs of dimorphic facial and lateral leaves with rounded to bluntly mucronate apices and rounded base, in each pseudo-whorl fused along most of their length to form a dorsoventrally flattened phylloclade-like segment, simple pseudo-whorls oval, triveined in surface view, wider pseudo-whorls at nodes of branching, expanded apically, showing five prominent longitudinal lines on either surface. Facial leaves adpressed, ob-triangular, with obvious central midvein, lateral leaves lanceolate to falcate, each folded along its midvein in the plane of compression, shorter than the facial, closely imbricate, more commonly fused to the margins of the facial leaves. Segments showing thickly cutinized epidermis with heavily papillate outer surface, non-modified cells irregularly disposed and stomata in irregular short rows, monocyclic to incompletely amphicyclic. A single incomplete seed cone with only three cone scales preserved was recovered in the Kristina Mine ( Holý 1975, pl. 2, fig. 1, recorded as Tetraclinis sp. and Kvaček 1989, pl. II(6), fig. 4, assigned to Tetraclinis salicornioides ). The probably unripen cone is 8-10 mm large, with decussately arranged cone scales of subtriangular outline, abaxially bearing a short mucro slightly below the middle of the scale length on radially striated bract area.

D i s c u s s i o n: The record does not deviate from the other of this species from Europe (see, e.g., Knobloch and Kvaček 1976, Walther and Kvaček 2007) and stresses the difference in seed cones between T. salicornioides with the subcentral mucro and T. brachyodon with the subapical mucro (Kvaček et al. 2000). Impressions of sterile foliage of Tetraclinis salicornioides are almost indistinguishable from an unrelated extinct cupressoid conifer Ditaxocladus S.X. GUO et Z.H. SUN occurring in the Late Cretaceous and the Palaeocene in the Northern Hemisphere ( Guo et al. 2012). The sprays of both conifers differ in the general form, which is slender elongate in Ditaxocladus and widely spread in Tetraclinis salicornioides . More pronounced differences are in the seed cones (subglobose in racemose fertile branches in Ditaxocladus vs quadrivalvate solitary, rarely paired in Tetraclinis ) and leaf anatomy (non-papillate straight-walled stomatal zones with thin Florin rings in Ditaxocladus vs thick and papillate cuticles with undulate anticlines and strong Florin rings around the stomatal pits in Tetraclinis salicornioides - see Guo et al. 2012). According to Kvaček et al. (2011), T. salicornioides may be better compared ecologically to Calocedrus macrolepis KURZ distributed in SE China, Myanmar ( Burma), Thailand and Vietnam based on its foliage physiognomy.

M a t e r i a l: Fragmentary branches isolated on slides, G 8874a-b, 8875a-b, 8876-78 (KR 238, 272, 323, 344, 345), a seed cone, G 4590.

Glyptrostrobus ENDLICHER