Abstract

The paper embodies description of a new species of the dispersed seed taxon Rugaspermum (Pant and Basu, 1977), R. stipitatus, from the Triassic beds of Nidpur, M.P., India. The new species is distinct from earlier described ones (R. insigne, R. media, R. obscura and R. minuta) in exhibiting a prominently demarcated wide stalk like rim at the chalazal end. The micropyle is short, tubular and not markedly protuberant. Seeds are about 3 mm long × 2 mm wide, orthotropous, platyspermic, oblong to oval with broadly tapered ends. Seed surface is rough often appearing wrinkled. On maceration the seeds yield four membranes viz., outer, inner, nucellar and megaspore membranes. Outer cuticle is papillate and stomatiferous. Inner cuticle is thin and delicate. Nucellar membrane is free above forming a large dome shaped pollen chamber but fused to megaspore membrane at base. Pollen chamber containing striate, unwinged, Rugapites Pant and Basu type pollen grains that are remotely comparable to the polyplicate pollen types of gnetophytes. Megaspore membrane is thick, dark and wide. Pollination is possibly entemophilous.

Keyword: Gymnosperm, in situ pollen grains, papillate, Rugaspermum, Seed, Triassic.