Mirovia szaferi Reyman.

Plant Fossil Names Registry Number: PFN002731

Act LSID: urn:lsid:plantfossilnames.org:act:2731

Author: M. Reymanówna

Rank: species

Genus: Mirovia Reyman.

Reference: Reymanówna, M. (1985): Mirovia szaferi gen. et sp. nov. (Ginkgoales) from the Jurassic of the Kraków Region, Poland. – Acta Palaeobotanica 25(1–2): 3–12., link

Page of description: 6

Illustrations or figures: fig. 1, pls I–III

Name is type for

Types

Original diagnosis/description

Leaves thick, coriaceous, straight to falcate, (5) 10–14 mm long but judging from fragments occasionally about 20 mm long, typically about 2 mm wide, extremes 1.6–3.5 mm, with a tapering occasionally twisted basis and a distinct transversely wrinkled petiole about 1 mm long, 1–1.5 mm wide, ending in crescent-shaped abscission scar 0.8–1 mm long, about 0.5 mm high. Leaf apex as a ru1e incomplete, with thick dark substance protruding between cuticles; when complete showing rounded end with small pointed tip, distinct from lustrous cuticle of remaining part of leaf, apparently covered with much thinner cuticle. Leaves polymorphic, dorsiventral with stomatal strip along middle of lower side, or bilateral with stomatal strip along leaf margin or intermediate. Frequently along each side of stomatal strip a cutinized ridge, protruding in most leaves so as to meet and hide the stomatal strip, at least in lower part of leaf. Approximately opposite the stomatal strip on the other side of the leaf a narrow longitudinal groove. Resistant to maceration filiform resin ducts about 0.1 mm wide consisting of a red-brown substance, usually two, occasionally three, straight or irregularly undulating but not dichotomising, running along leaf till apex.
Upper cuticle about 20 μm thick, consisting of longitudinal rows of quadrangular cells with almost straight walls and rounded corners, cells about 25 μm wide, their length 1–3 times their width. Periclinal walls mottled or with delicate punctuation, peripherally with delicate wrinkles running in different directions. Lower cuticle outside stomatal strip consisting of longitudinal rows of cells about 20 μm wide, their length up to 7 times their width, their periclinal walls smooth or with delicate longitudinal striation, occasionally 1–2 files of much narrower cells, otherwise like cells of upper cuticle.
One stomatal strip about 1 mm wide of much thinner cuticle, ordinary epidermal cells shorter and less regular than outside strip. Stomata crowded, arranged in 6 to 10 longitudinal files consisting of rows of up to 9 stomata; stomata in rows abuting with their guard cells or polar subsidiary cells, rows in a file separated by 1–4 ordinary epidermal cells. Occasionally additional short row of stomata inserted between stomatal files. Files of stomata abuting or separated by 1–4, occasionally more epidermal cells. Stomata arranged longitudinally, rarely (1 to 4) arranged transversely. Stomata 50–70 × 45–55 μm approximately circular occasionally elliptical typically with a ring of 4(–6) subsidiary cells, usually lateral cells longer than polar ones. Walls of subsidiary cells facing entrance of stomatal pit raised, forming a strongly cutinized ring, as a rule without papillae, entrance to stomatal pit quadrangular about 22 μm long 12 μm wide. Guard cells depressed, with thick cutin lamellae on outer walls and walls abuting on subsidiary cells.

Etymology

In memory of the late Professor Władysław Szafer of Kraków.

Stratigraphy

Jurassic, Middle Jurassic
Grojec clays (glinki grojeckie)

Locality

Poland
Zabierzów borehole