1�� Geological Museum of Jilin University��Changchun 130026��China; 2�� Key Laboratory of Evolution of Past Life and Environment in NE Asia��Ministry of Education��Changchun 130026��China; 3�� ��esearch Center of Palaeontology and Stratigraphy��Jilin University��Changchun 130026��China

Subgenus Phoenicopsis (Phoenicopsis) assigned to Czekanowskiales is recognized and a new species�� Phoenicopsis (Ph�� ) ordosensis sp�� nov�� is first reported from the Middle Jurassic Yan'an Formation of the Ordos Basin��alternate based upon the leaf gross morphology and epidermal structures�� The new species has linear leavs in bundles of five to six attached on a short shoot��more than 100 mm long by 5- 6 mm wide��containing 10- 12 parallel veins at upper portion�� The leaf is hypostomatic�� Epidermal cells are longitudinally arranged with smooth periclinal wall on the upper cuticle�� The narrow non- stomatal zones and wide stomatal zones alternate in the lower cuticle�� Stomata in four to five irregular spaced rows are longitudinally oriented in each stomatal zone�� Guard cells for each are surrounded by four to five subsidiary cells with undeveloped papillae�� Anticlinal walls of ordinary epidermal cells are nearly straight and periclinal walls slightly papillate�� The new species shallow stomatal pits kept open and surrounded by unevenly undeveloped bulges�� These characters are consistent with those of growth in a humid��rather than an arid climate�� The presence of subgenus Phoenicopsis and other taxa of Czekanowskiales in the coal- bearing Yan'an Formation supports the view that the climate in the Ordos Basin was humid and warm with seasonal changes during the Middle Jurassic��