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Protoyucca
Genus Protoyucca Tidwell, L.R. Parker Rev. Palaeobot. Palynol., 62(1–2): 82. 17 Jan 1990
- Name
- Protoyucca
- Rank
- Genus
- Authors (Pub.)
- Tidwell W. D.
Parker L. R.
- Publication
- Protoyucca shadishii gen. et sp. nov., an arborescent monocotyledon with secondary growth from the Middle Miocene of northwestern Nevada, U.S.A. [1990/1]
- Journal
- Review of Palaeobotany and Palynology
- Volume
- 62
- Issue
- 1–2
- Page number
- 82
- Year
- 1990
- Parent Taxon
- [Order] Asparagales
- Fossil Status
- stems (with leaves)
- Type
- Protoyucca shadishii
- Diagnosis
- Monocotyledonous, acaulescent to arborescent stems, primary cylinder atactostelic, of diffusely distributed collateral to amphivasal bundles. Secondary cylinder, surrounded by a secondary thickening meristem
(STM), composed of radially aligned, anastomosing collateral and amphivasal bundles, forming "growth-ring"-like structures. Phloem
within the bundles consist of sieve tube members and companion cells. Secondary cortex and successive layers of periderm are present. Leaves spirally arranged and abaxially keeled. Lobed stem bases with attached
adventitious roots having variable number of exarch xylem strands arranged in two concentric rings surrounded by thin-walled conjunctive tissue.
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