Article: Spores with bifurcate processes from the Middle Old Red Sandstone of Scotland

Plant spores are described from Middle Old Red Sandstone deposits of the Orcadian basin, Scotland. The genus Ancyrospora Richardson 1960 is reinterpreted. The species Hystricasporites corystus, Perotrilites bifurcatus, Ancyrospora longispinosa are new. In addition the most numerous spores are included in the species Ancyrospora ancyrea (Eisenack) comb. nov. which is subdivided into the varieties A. ancyrea var. ancyrea var. nov., A. ancyrea var. brevispinosa var. nov., and A. ancyrea var. spinobaculata var. nov. The range of variation of A. ancyrea is described in detail and compared at two different horizons. Finally the local and regional stratigraphic distribution of all these spores is discussed and their relative importance assessed. A new generic name Calyptosporites is proposed, in place of Cosmosporites Richardson (preoccupied).