Tanispermum E.M.Friis, P.R.Crane et K.R.Pedersen
Plant Fossil Names Registry Number: PFN001999
Act LSID: urn:lsid:plantfossilnames.org:act:1999
Reference: Friis, E. M., Crane, P. R. & Pedersen, K. R. (2018): Tanispermum, a new genus of hemi-orthotropous to hemi-anatropous angiosperm seeds from the Early Cretaceous of eastern North America. – American Journal of Botany 105(8): 1369–1388.
Page of description: 1371
Tanispermum hopewellense E.M.Friis, P.R.Crane et K.R.Pedersen
Fruit one- or two-seeded, indehiscent, with a thin fruit wall. Isolated seeds single or in pairs, small, bitegmic, and exotestal. Seeds irregularly elliptical, either with a single flattened contact face from the other seed, or with evenly rounded faces. Hilum and micropyle widely spaced and seeds hemi-orthotropous to hemi-anatropous. One set of vascular bundles extends from the hilum to chalaza (raphe). Micropyle in the inner integument (tegmen) differentiated into a thickened plug, and in the outer integument seen as a small irregular, lobed opening. Testa formed from an outer layer of tall palisade-shaped sclerenchyma cells (exotesta) and an inner zone of thin-walled, loosely packed cells (mesotesta/endotesta), several cell layers deep. Anticlinal walls of the palisade cells unevenly thickened, thicker toward the inside resulting in an obconical cell lumen or thicker toward the outside resulting in a conical cell lumen. Exotestal cells with undulate outer and inner parts of anticlinal walls resulting in stellate-undulate facets and a jigsaw puzzle-like pattern on the seed surface and the inner surface of the exotesta. Tegmen thin except close to the micropyle where it is sclerified. Embryo small. Nutritive tissue cellular.
Tanispermum is an anagram of Nitaspermum to indicate similarity to seeds of the fossil genus Nitaspermum (Friis et al., 2018b) and to indicate relationship to Nymphaeales and the families of Austrobaileyales (Illiciaceae, Trimeniaceae and Austrobaileyaceae).