【摘要】 <正> 本文记述的植物化石,产于吉林省双阳县上三叠统大酱缸组。该组出露于双阳县烧锅公社大酱缸、小石棚一带,呈东西向展布(插图1),是一套河湖沼泽相沉积的碎屑岩。主要岩性为:灰黑—灰色粉砂质板岩、粉砂岩,夹灰绿色凝灰质砾岩、凝灰岩及黄绿色砂砾岩等,局部夹煤层,厚1,439米。由于岩石普遍轻微变质,以往误认为是早二叠世地层。更多还原

【Abstract】 The present paper deals with the fossil plants collected from Dajianggang, Shuangyang County, central Jilin (about E, long. 125°48’ and N. Latd. 43°22’). The plantbearing Dajianggang Formation is composed chiefly of slightly metamorphosed silt-argillic slate intercalated with coal seams. The thickness of this formation is 1439 metres.This florule consists of over 21 species belonging to 13 genera, including 2 new species. They belong to Equisetales (19.0%), Filices (14.3%), Cycadophytes and Taeniopteris (both 28.6%), Ginkgophytes (14.3%) and Coniferales (23.8%) repectively. The presence of cf. Glossophyllum florini, Taeniopteris cf. leclerei, T. tenuinervis, Cladophlebis scariosa, Podozamites cf. distans and Drepanozamites etc. in this florule indicates a Late Triassic age. In the botanical characters, the florule seems to be close to the DictyophyllumClathropteris Flora. It bears a close resemblance in general aspect to some late Triassic floras, such as the Tianqiaoling flora of East Jilin, the Mongugai flora of Primorye of USSR, the Nariwa flora of Japan, and can also be correlated with some late Triassic floras of South-China. So the age of this florule. is considered to be of late Triassic, and most likely of Noric.The discovery of the late Triassic plants in the Dajiangang Formation overlain by the Xiaofengmidingzi Formation (composed chiefly of volcanic rocks) which is in turn overlain by the lower Liassic strata, is of considerable importance for studying the age of volcanic rocks distributed in Jilin and Northeast-China and the boundary between Upper Triassic and Lower Lias in this region.Descriptions of new species Equisetitesshuangyangensis sp.nov.Stem smooth; nodes slightly swollen; internodes about 6.5 cm. Long. Leaf-sheath 1.2 cm. long. Leaf segments about 18 in number, 1.6 mm. wide. Free leaf teeth typically 5 mm. long. Nodal diaphragm oval; spokes about 30 in number and about 2 mm. long in smallerdiaphragm; those in larger one 46 in number and about 5—6 mm. long. Cone unknown: E. sarrani Zeiller differs from the. present species in having more numerous (20—30) and less wide (0.5—0.75 mm.) leaf segfent, shorter free leaf teeth and sheath. E. praelongus Halle differs from the new species in having much longer (up to 3.5 cm.) free leaf, fewer (10—16) leaf segments, strongly swollen nodes and ribbed commissural furrows.Drepanozamites incisus sp. nov.Leaves large, about 11.3 cm. wide. Rachis thick (about 3 mm. wide) with obscure longitudinal striations. Pinnae large, about 5.5 cm. long and 1.1—1.5 cm. wide, with acuminate apex. Margin irregularly incised, lobes narrow (about 0.2—1 mm. wide) and long (about 2—10 mm.). Veins dense, dichotomising freely; one or a few veins supplying each lobe. Cuticle unknown.D. nilssoni (Nath.) Harris differs from the new species in having smaller pinnae and the entire or nearly entire margin. The specimens of Drepanozamites described from Upper Triassic of Lechang, Guangdong, China differs from the present form in having the threelobed-like apex of pinnae and acute lobelet near the lower margin of the apex.更多还原