Hydrangea microcalyx Hydrangea form and Raskya Chaneya Hydrangea Hydrangea Chaneya The Late Eocene Flora Of Kučlín Near Bílina In North Bohemia Revisited Kvaček, Zlatko Teodoridis, Vasilis Acta Musei Nationalis Pragae Series B 2011 2011-11-30 67 3 - 4 83 144 SIEBER SIEBER [988,1324,1828,1851] Magnoliopsida Hydrangeaceae Hydrangea Plantae Cornales 20 103 Tracheophyta species microcalyx  1881  Hydrangea microcalyx SIEBER, p. 16, pro parte, only figs 26, 27, 31. 1963  Hydrangea microcalyx SIEBER; Mai, p. 77, pl. 10, figs 7-9, text-fig. 13. Tetramerous petaloid calyces of sterile flowers 17–31 mmin the diameter, partly attached to straight stalks, showing scars at intervals of 7–9 mmafter fertile flowers, individual sepals obovate to broadly obovate, 6–12 mmlong and 4–10 mmbroad, in one whorl free, of almost the same size, entire, round to slightly emarginated apically, cuneate, shortly stipitate basally to subsessile. Venation camptodromous–brochidodromous to reticulate, thin wavy main vein gives raise two lateral veins soon radiating from the base, and a few higher secondaries at wide angles, tertiaries very fine, reticulate.  D i s c u s s i o n: Sterile persistent calyces of this hydrangea have been rarely found in the Kučlín diatomite, usually isolated. The slab with the illustrated types( Sieber 1881, NM G 337) shows two long stalked sterile flowers and confirms that the fossils came from widely ramified inflorescences of both sterile peripheral and fertile perfect flowers concentrated into dense groups. The latter are difficult to recognize in the impression material. Most other recovered fossils represent sterile florets.    Hydrangea microcalyxis the oldest record of this genus in Europe. Similar remains were more frequently reported from the Oligocene ( Walther and Kvaček 2007). Specific differences are difficult to recognize according to the morphology of sterile flowers only, which show uniform morphology even comparing impression material from the European and North American records ( Meyer and Manchester1997). Besides Kučlín, the richest sites of fossil hydrangeas in ČSM are connected with termophilic assemblages at Suletice ( Brabenec 1909, Kvaček and Walther 1995) and the Holý Kluk Hill (Radoň et al. 2003). A single flower has been lately recognized in the Late Oligocene flora of Rott, Rhineland (Winterscheid and Kvaček, in prep.). In no case the foliage belonging to the flowers has been suggested leaving the question open, if all records of these flowers belong to a single species. Tetramerous flowers of  Hydrangeadiffer decidedly by the broader form andvenation pattern from the extinct genus  Raskya, which produced similar tetramerous flowers and occurs at Kučlín (see below). The extinct genus  Chaneyacharacterized by persistent pentamerous flowers recently reinterpreted as persistent corollas (see above) superficially recalls sterile calyces of  Hydrangeaand can be easily mistaken for such remains. However, some of the typespecimens from Sośnica assigned to  Hydrangeashow remains of a pentamerous apocarpic gynoeceum typical of  Chaneya(  Manchesterand Zastawniak 2007) and differ also in the venation (five basal primaries).  Due to the quite diversified foliage morphology of the living hydrangeas ( McClintock 1957) it is a difficult task to suggest one from among the co-occurring morphotypes at Kučlín as belonging to the described flower remains. The stalked sterile flowers remaining on the periphery of variously formed inflorescences are characteristic of many of the ca. 80 living species. Considering the accompanying flora, most cultivated hydrangeas frost hardy are improbable living relatives, namely  H. paniculata SIEB. et ZUCCARINI( Japan, China), Perhaps  H. asperaD. DON(Himalayas to Java) or  H. quercifolia BARTR.(Florida) may come into question. M a t e r i a l s t u d i e d: NMG 337 (HOLO), NM G 7038a, b, G 75987, G 7892a, b.   Icacinaceae NM 21 104 G 337 1