| Abstract: | Ch. E. Weiss established the genus Palaeostachya in 1876, This genus represents the strobilus of Calamites. As a kind of reproductive organ, the Palaeostachya was first proposed to name Volkmannia by Sternberg but later had been renamed to Palaeostachya by Weiss (1876). In this paper two new species of Palaeostachya, Palaeostachya plagiobracteata sp. nov. and Palaeostachya densibrateata sp. nov., were collected from Lower Shihhotse formarion of Taiyuan in Shanxi Province, and they are described here. Palaeostachya plagiobracteata sp. nov. is a very interesting strobilus, of which both basal and upper parts are not preserved. The specimen of the strobilus is about 2.5 cm long and 1.2 cm in the greatest dismeter. Bracts which extend horizontally from the axis and then turn upward are well preserved. Two rows of them are rather conspicuously. Bract is about 4 mm. long, upper part is about 1 mm. Axis is about 2 mm in width. Four rows of sporangia are distinctly around the axis. The sporangia are sessile, rather large, oblong-ovate in shape, and attach directly to the basal part of bract in an axillary position. Horizon and Locality: Lower Shihhotse formation. Tungshan, Taiyuan, Shanxi. Palaeostachya densibracteata sp. nov. is an important strobilus, of which basal and tip parts are very well preserved. The basal part of sterigma of strobilus is preserved. There are many lepidosomes on the sterigma. Lepidosome is about 3 mm in width and its tip is well preserved. Strobilus is similar to ear of corn in shape about 3 cm long, 1.5 cm. in width. Bracts are well preserved. Six rows of them are more conspicuously in the specimen. The bracts extend horizontally from the axis and then turn upward nearly parallel with the axis. The tip part of each bract appears short triangle, but basal part is contiguous. Sporangia are not preserved in the specimen. Horizon and Locality: Lower Shihhotse formation; Tungshan, Taiyuan, Shanxi. |
