Tasymia

Name

Tasymia

Rank

Genus

Authors (Pub.)

Golovneva L. B.  

Publication

Novyj rod platanovykh Tasymia (pokrytosemennye) iz turona Sibiri [2008]

Journal

Paleontologicheskii Zhurnal

Annee/Jahrgang

2008

Issue

2

Page number

88

Year

2008

Parent Taxon

[Family] Platanaceae

Fossil Status

leaves

Type

Tasymia pseudoplatanoides

Diagnosis

Leaves simple, the lamina rounded, deltoid or broadly ovate in outline, frequently broader than long, with 3–5 lobes or lobe-like projections, acute, truncate or cordate base and broadly triangular or obtuse apex. Lobes rounded or triangular with obtuse apex and small, rounded sinuses, decreasing upwards. Margin dentate; teeth small, broadly triangular, with glands at the apex and rounded sinuses. Venation pinnate or pinnate-palmate, craspedodromous, 5–6 pairs of secondary veins diverge from main vein at the angle about 50°, usually straight or slightly curved, and 1–2 pairs of thin sub-basal veins diverge below the basal veins. The epidermis comprises sinuous–walled, isodiametric or elongated, irregular in shape ordinary cells. The adaxial epidermis covered by numerous compound trichome bases. The abscission scars appear as thickened rings about 20–50 μm across, surrounded by radial striation of outer surface and are situated over the junction of several underlying specialized (smaller and more thickened) epidermal cells. The abaxial epidermis has scattered anomocytic stomata, compound trichome bases and numerous glandular trichomes. Stomata are broadly oval in outline attaining 20–27 μm in length with elliptical aperture and thickened stomatal ledges. Glandular trichomes capitate, stalked or sessile, about 10–15 μm in diameter, associated with one epidermal cell. On inner cuticle surface, the positions of papillalike stalks of glandular trichomes are marked by apertures in the central part of underlying cell.