论文研究了采自中国内蒙古宁城道虎沟中侏罗世的化石标本，通过枝叶形态特征对比，该化石属于柏科。论文比较了该化石与柏科燕辽属、红杉属、水杉属、落羽杉属、水松属的枝叶特征和表皮结构，将化石定为红杉属的热河红杉，并详细描述了热河红杉的表皮结构。论文讨论了表皮结构在分类中的意义，并对当时的环境进行了初步分析。

Compressions of Sequoia (Cupressaceae sensu lato) from the Middle Jurassic of Daohugou, Ningcheng, Inner Mongolia, China

Qing-Wen Ma1 & David K. Ferguson2 & Hai-Ming Liu1 & Jing-Xian Xu1

Abstract：The specimens (two pairs of part and counterpart) of coniferalean branched leafy shoots were collected from the Jiulongshan Formation (Middle Jurassic) at the village of Daohugou, Ningcheng, Inner Mongolia, China. The fossil material displays helical phyllotaxy, dorsiventrally flattened linear, sessile leaves with decurrent base and prominent and single mid-vein. The foliate shoots are assigned to Sequoia jeholensis by comparing those of the genera Yanliaoa, Sequoia, Metasequoia, Taxodium, and Glyptostrobus, the basal members of the Cupressaceae sensu lato. Sequoia jeholensis is the oldest Sequoia species to date. It has coriaceous, dimorphic, helically arranged linear and scale leaves, with entire margins, attached obliquely to the axis by their decurrent bases. The leaf cuticle of S. jeholensis is described here for the first time. Leaves are hypostomatic, with stomata only on the abaxial surface. Anticlinal walls are straight, with single or more often paired pits. The epidermal structures of Sequoia are one of the key characters to distinguish it from similar genera, but they usually could not be used to distinguish the species within Sequoia. The Middle Jurassic of Daohugou represents a lacustrine environment with a warm and humid climate reflected by the species assemblage. So, the extinct Sequoia probably had similar climatic requirements to those of extant Sequoia sempervirens.

Keywords Cupressaceae s.l.. Sequoia. Cuticle. Middle Jurassic. Jiulongshan Formation. China