Ulmus furcinervis (Borsuk) Ablaev is first recognized and described in the Paleocene Wuyun flora from Heilongjiang Province, China. The combination of key characteristics for identification of these leaf specimens is that they have craspedodromous secondary veins forked near the leaf marginal, tertiary veins percurrent and marginal teeth convex. Specimens formerly described as leaves of Planera cf. microphylla auct. non Newberry and Sorbaria wuyunensis Tao et Xiong in Wuyun flora are reexamined and assigned to U. furcinervis.
该文综述了北京地区全新世以来植被演替和气候变化的相关研究资料,这些资料反映了当前阶段对该地区该时段植被与气候环境格局特征的认识。北京地区全新世早期(约12 000–8 000 cal a B.P.)植被为森林草地和/或针叶树占主导的针阔混交林,森林中阔叶树类群逐渐增多,指示了气候由寒冷干燥转为温暖湿润;全新世中期(约8 000–2 000 cal a B.P.前后)植被为暖温带针阔混交林,指示暖湿气候;全新世晚期(约2 000 cal a B.P.以来)转为森林草地和/或针叶树占主导的针阔混交林,气候转向凉干。植被演替反映的湿润度变化与季风区其它地区变化趋势一致。值得注意的是,前人研究揭示北京地区山区与平原中植被类型和类群组成已经出现空间分异。今后如能深入开展定量古气候重建研究,有可能精确描述其气候变化的过程,增进中国不同地理单元同时期气候变化的对比。
Numerous leaf compressions of Glyptostrobus europaeus (Brongn.) Ung. (Taxodiaceae) are found in Aquitanian (Lower Miocene) lignified clay localities Bolattam and Akzhar in the Southern Turgay, on the right bank of the Dulygaly-Zhilanshik river (Central Kazakhstan). The finely preserved lignified compression remains of leafy shoots make micro-morphological investigation feasible. Comparative studies of the epidermal features both living G. pensilis C. Koch and a new finding of G. europaeus from Early Miocene of Kazakhstan and illustrate their certain difference. The cuticular organization and epidermal features of fossil leaves, which have been compared with these of 'the nearest living relative', G. pensilis, were studied by scanning electron microscopy (SEM) and light microscopy (LM). The fossil leaves of G. europaeus from Kazakhstan are distinguished by stronger, than in living species, G. pensilis, developed 'micro-papillae' ('Kristallucken'), visible in SEM as ring-like structures left on the outer surface of cuticle in both nonstomatal and stomatal zones.
Sergei Vasilyevich VICKULIN马清温Sergey Glebovich ZHILIN李承森
