XIV.—Some Lower Carboniferous Fructifications from Berwickshire, together with a Theoretical Account of the Evolution of Ovules, Cupules, and Carpels

Abstract

SynopsisTwo new species of petrified seedsEosperma edromense, andAnasperma burnensegen. et sp. nov. are described from the Cementstone Group of Berwickshire.Anaspermashows that the anatropous condition existed among Palæozoic ovules; it has a single integument with two lateral apical lobes.Rachides ofStauropteris berwickensissp. nov. and associated megasporangia are also described.An account is given of the theory of the telomic origin of the first ovular integument. The second (outer) integument in Angiosperm ovules may therefore have evolved after the establishment of anatropy, either from the first integument or as an overgrowth of the chalaza. Evidence is cited to support the theory that Angiosperm carpels have evolved from dorsiventral bivalved cupules.