A New Gleicheniaceous Fern Chansitheca (Sphenopteris) wudaensis from the Lower Permian of Wuda, Nei Mongol, China

内蒙古乌达地区早二叠世晋囊蕨属一新种(英文)

Chansitheca (Sphenopteris) wudaensis sp. nov. is described based on the materials collected from the Lower Permian Shansi Formation of Wuda, Nei Mongol, China. The frond is small and at least two times pinnate. The pinnule is sphenopteroid. The sori are borne on the abaxial surface of the pinnule, arranged in two rows parallel to the midvein, elliptic,and composed of 4-10 round sporangia. The indusium is absent. The annulus is transverse and complete, and consists of about 18 thickened cells. The features of the fertile parts, sori, sporangia and annulus and the absence of indusium indicate that the new species belongs to the Gleicheniaceae.

通过扫描电镜研究 ,建立了内蒙古中部乌达地区下二叠统山西组晋囊蕨属的一个新种Chansithecawudaensissp .nov .。新种的小羽片Sphenopteris型 ;囊群椭圆形 ,由 4～ 10个孢子囊组成 ,着生于小羽片背面 ,位于中脉的两侧 ;环带横列于孢子囊的上部 ,完全 ,单排细胞 ,细胞数目约为 18个。这些特征表明新种属于里白科。