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Yavanna
Genus Yavanna E.I. Vera Cretac. Res., 2013, (10.1016/j.cretres.2013.04.011): 2. 22 May 2013
- Name
- Yavanna
- Rank
- Genus
- Authors (Pub.)
- Vera E. I.
- Publication
- New cyathealean tree fern, Yavanna chimaerica gen. et sp. nov., from the Early Cretaceous of Livingston Island, Antarctica [2013/5]
- Journal
- Cretaceous Research
- Annee/Jahrgang
- 2013
- Issue
- 10.1016/j.cretres.2013.04.011
- Page number
- 2
- Year
- 2013
- Parent Taxon
- [Family] Cyatheaceae
- Fossil Status
- stems
- Type
- Yavanna chimaerica
- Diagnosis
- Fossil tree fern stem with attached petiole bases
and adventitious roots. Internally, presenting a solenostele and
accessory medullary bundles, both surrounded by a sclerenchyma
sheath. Pith and cortex parenchymatous, the latter enclosed by the
hypodermis. Proximal petiole bases vascularized by one corrugate
meristele, arranged in a modified omega-shaped structure, with a
pair of deep lateral constrictions. Distal petiole bases with three
meristeles, resulting from the division of the single meristele in two
adaxial arcs and one abaxial arc. Corrugations of vascular strands of
the petiole base due to the repetition of V-shaped units. Adventitious
roots protostelic, with internal parenchymatic and external sclerenchymatic
cortex.
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