Plenasium xiei

Name

Plenasium xiei

Rank

Species

Generic Name

[Genus] Plenasium

Authors (Pub.)

Cheng Y.-M. Liu F.-X. Tian N. Jin Y.-G. Sun T.-X.  

Publication

Plenasium xiei sp. nov. from the Cretaceous of Northeast China: Additional evidence for the longevity of osmundaceous ferns [2019/7]

Journal

Journal of systematics and evolution

Annee/Jahrgang

2019

Issue

10.1111/jse.12532

Page number

4

Year

2019

Fossil Status

stems

Stratigraphy

Cretaceous

Strat. comment

undetermined

Location

Erlongshan Farm (No. 5), Wudalianchi City, Heilongjiang Province, northeast China

Paleoregion

Eurasia (China)

Data for Holotypus

Repository

Geological Museum of China, Beijing, China

Repository Number

P3122

Num

Figs. 2, 3, 8

Pub.

Plenasium xiei sp. nov. from the Cretaceous of Northeast China: Additional evidence for the longevity of osmundaceous ferns [2019/7]

Data for Paratypus

Repository

Geological Museum of China, Beijing, China

Repository Number

P3123 (Figs. 4–7); P3124 (Figs. 9, 10)

Num

Figs. 4–7, 9, 10

Pub.

Plenasium xiei sp. nov. from the Cretaceous of Northeast China: Additional evidence for the longevity of osmundaceous ferns [2019/7]

Diagnosis

Fossil rhizome consisting of central stem surrounded by a mantle of petiole bases and adventitious roots. Stem diameter up to approximately 20 mm, with ectophloic‐dictyoxylic siphonostele and two‐layered cortex. Pith heterogeneous, composed of ground parenchyma and abundant sclerenchyma strands. Stele cylinder with ca. 11–14 vascular bundles, 25–33 tracheids thick. Leaf trace with two protoxylem bundles by fusion of two adjacent xylem bundles with one protoxylem bundle once separated from stele. Inner cortex ca. 1–1.5 mm thick, containing 2–4 C‐shaped leaf traces. Outer cortex ca. 2–3.7 mm thick, with ca. 13–16 leaf traces. A single, lobed sclerenchyma band occurring at the adaxial side of stelar xylem strands, in the leaf trace concavity, and adaxial to the vascular bundles of proximal petiole bases, separating distally into many smaller groups, usually connected by few cells in transverse view. Petiolar sclerenchyma ring strong and heterogeneous. Petiolar inner cortex containing many large sclerenchyma strands. Abundant sclerenchyma strands, both in bundles and singly in stipular wing.