Early Silurian microfossil plants from the upper part of the Xiushan Formation in Guizhou Province, China and their palaeobotanical significance

Abstract

The upper part of the Xiushan Formation outcropped at Fenggang, N. Guizhou, China, containing the megafossil plant Pinnatiramsos qianensis Geng, yields a remarkable assemblage of trilete spores (12 species referred to 5 genera), tetrads and acritarchs (11 species referred to 8 genera),tubular elements (6 species referred to 3 genera), leiosphere clusters and cuticle-like fragments (3 types). Evidence from a variety of fossil animal groups indicates that this stratum should be late Llandovery (Telychian). The discovery of trilete and retusoid spores and dispersed tubular elements provide reliable clues to suppose that vascular

Plants had come into existence in the Early Silurian. The presence of tracheids with border pits suggests that Pinnatiramosus qianensis is most likely the oldest known vascular plant.