Comptonia difformis (STERNBERG) BERRY

Kvaček, Zlatko, Teodoridis, Vasilis & Zajícová, Jana, 2015, Revision Of The Early Oligocene Flora Of Hrazený Hill (Formerly Pirskenberg) In Knížecí Near Šluknov, North Bohemia, Acta Musei Nationalis Pragae Series B 71 (1 - 2), pp. 55-102 : 65-66

Comptonia difformis (STERNBERG) BERRY

Pl. 6, fig. 6, Pl. 13, Fig. 1–8

1961 Comptonia difformis (STERNBERG) BERRY ; Knobloch, p. 257 pro parte (non infructescence on pl. 3, fig 6 left = Platanus neptuni ), pl. 3, fig. 4–7, 9–10, pl. 12, fig. 6, pl. 15, fig. 8.

Leaves coriaceous, variable in size from minute specimens hardly attaining 21 mm in length and 5 mm in width to larger, up to 80 mm long, acuminate, at base abruptly narrowing into a short petiole. Leaf lamina pinnately dissected into triangular rounded segments (lobes) at base reaching usually to the midrib, opposite to alternate, variable in size and form in this respect matching the living Comptonia peregrina L. Segments at apex usually blunt, but also mucronate; 2–8 perpendicular secondaries entering the lobes, three of them are usually thicker than the others and stretch to the margin from the straight midrib. They are connected by oblique tertiary veins that form a polygonal field ( Knobloch 1958, translated from Czech, emended). The newly obtained epidermal structure is very fragmentary. Adaxial cuticle is smooth and shows outlines of cells ca. 20–25 µm in diameter with almost straight to wavy anticlines. Abaxial cuticle is extremely thin, hairy, and shows rounded short uniseriate stalks ca. 12 µm in diameter and even disc-shaped glandular trichomes up to 50 µm in diameter.

D i s c u s s i o n. The occurrence of Comptonia in the European Palaeogene is connected with two fossil species, C. difformis later widely spread in the Neogene and the more xeromorphic, small-leaved C. dryandrifolia BRONGNIART (= C. schrankii (STERNBERG) BERRY ). The population from

Knížecí corresponds to C. difformis morphologically, as stated by Knobloch (1961), as well as in epidermal anatomy. In general the epidermal structure matches that obtained from leaves of Comptonia difformis from the upper Oligocene of Kleinsaubernitz ( Walther 1999).

M a t e r i a l s t u d i e d: Leaf compressions-impressions, NM-G2826, NM-G2827, NM-G2829, NM-G2831, NM-G2986, NM-G2987, NM-G2988, NM-G2989, NM-G2830, NM-G11502a, b, EK 290–302, numerous specimens not numbered.