Chinese Bulletin of Botany ›› 2000, Vol. 17 ›› Issue (专辑): 179-183.

• 研究报告 • Previous Articles     Next Articles

Asterotheca of Permian in Pingdingshan of Henan Province and Its Relationship with Scolecopteris

WANG Hong-Shan SHENG A-Xing YANG Guan-Xiu   

  1. (China University of Geosciences, Beijing 100083)
  • Online:2000-12-20 Published:2000-12-20

Abstract: Three species of Asterotheca, i.e. Asterotheca sahnii Hsu, Asterotheca orientalis (Shenk) Pot. and Asterotheca arborescens (Stem) Stur are reported in this paper. The compression specimens with well-preserved reproductive organs were collected from black mudstone of Xiaofengkou Formation of Middle Permian in Pingdingshan Coalfield of Henan province, Central China. In situ synangia, sporangia and spores of the three species were described in detail. Synangia of Asterotheca sahnii and Asterotheca arborescens consist of 4 sporangia, which are laterally asymmetric narrow ovate. Spores are monolete with smooth exine. A. sahnii is distinguished from A. arborescens by (1) its synangia are distributed only on the proximal to middle portion of the pinule while those of the latter occupy the entire pinnule and (2) the length/width ratio of its pinnule is larger than that of A. arborescens; Synangium of Asterotheca orientalis consists of 6 sporangia, which are also narrow ovate and asyrmmetric. Spores are monolete with verruculose exine. Based on Chinese specimens, differences between Asterotheca and Scolecopteris are: (1) pinnules of Scolecopteris show morphological variations, with most of the fertile pinnules narrower, or wider and shorter than vegetative ones and abaxially curved, while fertile and vegetative pinnules of Asterotheca are synmorphic and are smaller than those of Scolecopteris; (2) synangium of Scolecopteris from China consists of 4 elongate columnar and larger sporangia with a short receptacle. For example, Scolecopteris cathaysicus, which is from the same horizon as Asterotheca from the Pingdingshan Coalfield of Henan Province, has elongate columnare sporangium up to 1.8-2.2 mm long. Sporangia of the three species of Asterotheca are smaller, asymmetric and narrow ovate, generally less than 1 mm long and sessile, no fusion between adjacent sporangia and are easily to be separated after processed in Schulze solution; (3) generally, there are 10-12 synangia (up to 16, at least 7) synangia on each side of the midvein on one pinnule of the three Chinese species of Scolecopteris, while the number of synangia on one pinnule of three species of Asterotheca described in this paper rarely exceeds 6. Based on features of frond morphology and reproductive organs observed from the Chinese specimens, Asterotheca and Scolecopteris are easily to be distinguished and probably both are natural genera of the Paleozic Marattiales.