Arazedispermum

Name

Arazedispermum

Rank

Genus

Authors (Pub.)

Friis E. M. Crane P. R. Pedersen K. R.  

Publication

Chlamydospermous seeds document the diversity and abundance of extinct gnetalean relatives in early cretaceous vegetation [2019/7]

Journal

International Journal of Plant Sciences

Volume

180

Issue

7

Page number

000 [13] 655

Year

2019

Parent Taxon

[Phylum] Gnetophyta

Fossil Status

seeds

Type

Arazedispermum lusitanicum

Diagnosis

Seeds small and orthotropous. Integument free from the seed envelope for its full length except at the base, where it is broadly attached. Integument apically extended into a long micropylar tube formed by an inner and an outer epidermis. Micropylar canal open apically but closed farther down by the cells of the inner epidermis that expand radially toward the center of the canal. Seed envelope broadly elliptical in lateral view, elliptical and weakly four angled in transverse section, extended in the micropylar region into a short central projection supporting the micropylar tube. Outer surface of seed envelope almost smooth; outer epidermis of equiaxial cells covered by a thick cuticle. Inner surface of seed envelope smooth in the micropylar region, lacking papillae. Sclerenchyma zone of seed envelope consisting of an inner layer of equiaxial stone cells; a middle layer of narrow, radially and longitudinally extended cells; and an outer layer of very small isodiametric cells.