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Drepanophycus qujingensis
Drepanophycus qujingensis C.-S. Li, D. Edwards Bot. J. Linn. Soc., 118(3): 190. Jul 1995
- Name
- Drepanophycus qujingensis
- Rank
- Species
- Generic Name
- [Genus] Drepanophycus
- Authors (Pub.)
- Li C.-S.
Edwards D.
- Publication
- A re-investigation of Halle's Drepanophycus spinaeformis Göpp. from the Lower Devonian of Yunnan Province, southern China [1995/7]
- Journal
- Botanical Journal of the Linnean Society
- Volume
- 118
- Issue
- 3
- Page number
- 190
- Year
- 1995
- Fossil Status
- stems (with sporangia)
- Stratigraphy
- Emsian
- Strat. comment
- Xujiachong Formation
- Location
- road between Xujiachong and Xichong villages, Qujing City, eastern Yunnan Province, China
- Paleoregion
- Cathaysia (South)
Data for Holotypus
- Repository Number
- CBYn 9001001
- Diagnosis
- Plant with leafy vegetative and fertile stems up to 25 mm wide (excluding leaves) with infrequent dichotomous branching in main stems which bear lateral buds and narrow unbranched lateral stems « 5 mm wide) with more crowded leaves. Persistent leaves on major/main stems with subulate to ensiform laminae « 10 mm long and 2 mm wide) lacking petioles helically inserted with c. 10-12 leaves/gyre. Leaves on main stem falcate to horizontal with recurved tip with abaxial curvation except at apex of shoot where adaxially curved and more crowded. Leaves on lateral branches lanceolate to acicular and directed apically, reflexed only near base of biggest examples. Leaves vascularized to tip and supplied by narrow undivided trace. Epidermal cells normally 5-6 times longer than wide « 292 [lm long) each longitudinally orientated with a superficial centrally placed longitudinal ridge or < 2 times longer than wide showing no consistent orientation. Only elongate cells on leaves. Stomata anomocytic. ? lobed xylem; protoxylem elements with annular and spiral thickenings and interconnecting wall with pits of varying shape; « 570 nm diameter) metaxylem thickenings similar with smaller less frequent rounded pits (c. 70 nm diameter). Adventitious roots « 3 mm diameter) randomly borne on sterile and fertile stems branch < 5 times dichotomously, < 30 mm long supplied by broad vascular traces. Fertile axes of similar dimensions to sterile with zones of sporangia. Sporangia borne erect on short stalks « 1 mm long) arising directly from stems have two equal valves, elliptical transversely (3.0-3.5 mm high by 3.5-5.0 mm wide) or longitudinally (3.0-4.5 mm high by 2.5-3.5 mm wide) or circular (2.0-3.0 mm diameter). Dehiscence around entire free convex margin. Plane of dehiscence vertical and tangential to stem. Junction with stalk slightly concave.
