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Yuguangia ordinata
Yuguangia ordinata S.-G. Hao, J.-Z. Xue, Q. Wang Int. J. Pl. Sci., 168(8): 1163. Oct 2007
- Name
- Yuguangia ordinata
- Rank
- Species
- Generic Name
- [Genus] Yuguangia
- Authors (Pub.)
- Hao S.-G.
Xue J.-Z.
Wang Q.
- Publication
- Yuguangia ordinata gen. et sp. nov., a new lycopsid from the Middle Devonian (Late Givetian) of Yunnan, China, and its phylogenetic implications [2007/10]
- Journal
- International Journal of Plant Sciences
- Volume
- 168
- Issue
- 8
- Page number
- 1163
- Year
- 2007
- Fossil Status
- stems (with sporangia)
- Stratigraphy
- Givetian
- Strat. comment
- Haikou Formation
- Location
- Yuguang village, Zhanyi District, Yunnan Province, China
- Paleoregion
- Cathaysia (South)
Data for Holotypus
- Repository
- Beijing University, Department of Geology, Beijing, China
- Repository Number
- BUP.H-y07
- Diagnosis
- Proximal stems branch isotomously at a wide angle (ca. 80–120), ca. 10 mm wide exclusive of leaves, with 16–18 leaves per gyre. Leaf base 0.8–1.2 mm long and 0.3–0.5 mm wide, with an upper bulge and a gradually tapered and decurrent base. Distal shoots ca. 2–4 mm in width. Leaf pedicels departing from axis at a right or oblique angle, ca. 1.6–3.0 mm long and 0.6–1.4 mm wide. Laminae, triangular in shape, with bases ca. 1.0–2.5 mm wide and thinning distally, ca. 7–15 mm long. Terminal strobili composed of eight sporophylls per gyre. Sporophyll pedicels 0.7–2.8 mm long and 0.3–0.6 mm wide, departing from stem at a right angle. Sporophyll lamina triangular in shape, 8–10 mm long; its base 2.0–3.0 mm wide, curved slightly toward the fertile axis, partly enclosing sporangia. Megasporangia and microsporangia similar in dimensions, 1.8–2.4 mm wide, ca. 1.8 mm high, and 0.8–1.3 mm thick. Megaspores ca. 450–832 mm in diameter. Laesurae extend over four-fifths of the spore radius and are ca. 180–320 mm high. Microspores ca. 60–75 mm in diameter, ca. 4–6 mm thick in distal wall. Distal surface covered with isolated or fused tuberculi, ca. 2–5 mm in diameter, bearing papillae and coni ca. 0.5–1 mm wide and 1 mm high. Xylem strand of distal axis circular to elliptical, 690–730 mm in diameter. Protoxylem tracheids round or polygonal in transverse view, ca. 4–12 mm in diameter. Metaxylem tracheids polygonal, ca. 13–35 mm in diameter. Perforations 0.5–4.2 mm in diameter. Sixteen protoxylem exarch areas at the periphery of stele, where each successive gyre of eight leaf traces are emitted. Inner cortex consists of larger parenchyma cells, while outer cortex consists of thick-walled cells.
