Quadrispermum E.M.Friis, K.R.Pedersen et P.R.Crane

Plant Fossil Names Registry Number: PFN001967

Act LSID: urn:lsid:plantfossilnames.org:act:1967

Authors: E. M. Friis, K. R. Pedersen & P. R. Crane

Rank: genus

Reference: Friis, E. M., Pedersen, K. R. & Crane, P. R. (2013): New diversity among chlamydospermous seeds from the Early Cretaceous of Portugal and North America. – International Journal of Plant Sciences 174(3): 530–558.

Page of description: 543

Type

Original diagnosis/description

Seeds small and orthotropous, borne in the axils of opposite bracts. Integument free from seed envelope for its full length except at the base where it is broadly attached. Integument apically extended into a long micropylar tube that extends beyond the seed envelope. Micropylar tube lined by an inner and outer epidermis. Micropylar canal open apically and closed farther down by cells of inner epidermis that expand radially toward the center of the canal. Seed envelope ellipsoidal to ovoid and distinctly four angled in cross section except at the base where it is circular to elliptical. Surface of seeds with irregular transverse ridges forming a coarsely rugulate pattern. Seed envelope extended in the micropylar region into a short, collar-like central projection supporting the micropylar tube and laterally into four small knob-like protrusions. Micropylar tube interlocked with seed envelope proximally by small pits in its outer surface that correspond to oblique, upwardly directed papillae on seed envelope. Inner epidermis of seed envelope of relatively large longitudinally elongated polygonal cells with thin cell walls. Outer epidermis of seed envelope of narrow, longitudinally elongated cells with a thick cuticle. Seed envelope with an inner sclerenchyma zone and an outer zone of nonlignified cells. Sclerenchyma zone with inner layer of narrow, transversely elongated cells and outer layer of shorter, longitudinally elongated cells. Apically, inner sclerenchyma cells enlarged and extended radially. Outer zone poorly developed.

Etymology

From the four-angled shape of the fossil seeds (Latin: quadri for ‘‘four’’; Greek: sperma for ‘‘seed’’).