Xenoxylon shimakurae

Name

Xenoxylon shimakurae

Rank

Species

Original spelling

shimakurai

Generic Name

[Genus] Xenoxylon

Authors (Name)

Yamazaki S. Tsunada K.  

Authors (Pub.)

Yamazaki S. Tsunada K. Hagiwara I.  

Publication

Comparison between the Liassic and Neocomian species of Xenoxylon Gothan occurring in the Hida Terrane, Central Japan [1984/3]

Journal

Memoirs of the School of Science and Engineering / Waseda University

Issue

48

Page number

94

Year

1984

Fossil Status

stems (wood)

Stratigraphy

Lower Jurassic

Strat. comment

Negoya Formation, Liassic Kuruma Group

Location

Kitadani Valley, Asahi-machi, Toyama Prefecture, Japan

Paleoregion

Eurasia (Japanese Archipelago)

Data for Holotypus

Repository

School of Science and Engineering, Waseda University, Tokyo, Japan

Repository Number

830901

Num

Pl. I, Figs. 1- 4; Pl. II, Figs. 1-3; Pl. III, Figs. 1-2; Pl. IV, Figs. 1-3; Text-figs. 1-2

Pub.

Comparison between the Liassic and Neocomian species of Xenoxylon Gothan occurring in the Hida Terrane, Central Japan [1984/3]

Diagnosis

Coniferous wood with pith, consisting of tracheids and ray parenchyma, devoid of resin canals and wood parenchyma. Growth rings present; early wood open, late wood distinct and narrow, transition from early to late wood more or less abrupt. Bordered pits on radial walls of early wood tracheids elliptical in outline, horizontally elongated and vertically flattened, 30-32 11m in horizontal and vertical diameters respectively; arranged always contiguously and mostly in one row, rarely in two rows, alternate and/ or opposite when in two rows, with circular or oval pit-apertures. Bordered pits on radial walls of late wood tracheids relatively small, circular in outline, 15-18 11m in diameter; arranged always in one row, partly in contact and partly separately. Bordered pits on tangential walls of late wood tracheids present, less abundant, small, circular in outline, ca. 13 ,urn in diameter; arranged mostly in one row, rarely in two alternating rows, with circular or oval pit-apertures. Crassulae apparently absent. Thin-walled tyloses abundant in the lumina of both early and late wood tracheids, presenting septum- or bubble-like shape. Rays all parenchymatous, uniseriate, rarely biseriate in part, 1-16, mostly 3-7 cells high: horizontal and tangential walls thin and smooth, lateral walls with large and oval simple pits, mostly one, rarely two in each cross field of early wood; always o~e, somewhat lenticular and inclined simple pits in that of late wood. Pith consists of parenchymatous cells and secretory (mucilaginous) cells; the latter cells scattered isolatedly or grouped in cluster of two or three, not surrounded by epithelial cells. Development of primary xylem endarch, tracheary elements of protoxylem have spiral and/ or ring thickenings.