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Nitaspermum
Genus Nitaspermum Friis, P.R. Crane, K.R. Pedersen in M. Krings, C.J. Harper, Cúneo, G.W. Rothwell Transf. Paleobot. 418. 20 Jul 2018
- Name
- Nitaspermum
- Rank
- Genus
- Authors (Pub.)
- Friis E. M.
Crane P. R.
Pedersen K. R.
- Publication
- Fossil seeds with affinities to Austrobaileyales and Nymphaeales from the Early Cretaceous (Early to Middle Albian) of Virginia and Maryland, USA: new evidence for extensive extinction near the base of the angiosperm tree [2018/7]
- Authors (Book)
- Krings M.
Harper C. J.
Cúneo N. R.
Rothwell G. W.
- Book
- Transformative Paleobotany
- Page number
- 418
- Year
- 2018
- Parent Taxon
- [Order] Nymphaeales
- Fossil Status
- seeds
- Type
- Nitaspermum taylorii
- Diagnosis
- Seeds small, anatropous, bitegmic
and exotestal, narrow to broadly elliptic in lateral view,
bilaterally symmetrical with dorsiventral plane of symmetry,
sometimes slightly compressed laterally. Raphe indistinct
externally. Hilum and micropyle close together
separated by a narrow zone of exotestal tissue. Hilum with,
or without, a hilar rim. Micropyle formed by the inner
integument (tegmen) and marked on the seed surface by a
transverse slit through the outer integument (testa) adjacent
to hilum. Testa formed from an outer layer of palisadeshaped
sclereids and an inner layer of thin-walled parenchyma
cells. Palisade cells of exotesta with evenly
thickened walls and a straight lumen. Palisade cells over
most of the seed body with outer and inner parts of their
anticlinal walls strongly folded resulting in a jigsaw puzzlelike
pattern on the seed surface. Exotestal cells surrounding
hilum and micropyle with polygonal facets. Tegmen thin.
Embryo tiny.
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