Further evidence for diversity in late Silurian land vegetation

Small coalified plant fragments from basal Pridoli (Silurian) strata at Perton near Hereford, England comprise isotomously branching smooth axes terminating in vertically elongate sporangia. The latter, which occasionally bifurcate, are characterized by prominent, distally concentrated, spinous emergences and contain trilete, retusoid, smooth-walled isospores. The plants are placed in a new genus and species, Caia langii. Comparisons are made with a number of Silurian and Lower Devonian plants with elongate sporangia and particularly with Horneophyton. A hypothesis is developed that spines on sporangia had a nutritive function. The spores are discussed in terms of other records of late Silurian-Early Devonian in situ spores.