Longstrethia

Name

Longstrethia

Rank

Genus

Authors (Pub.)

Upchurch G. R., Jr. Dilcher D. L.  

Publication

Cenomanian angiosperm leaf megafossils, Dakota Formation, Rose Creek locality, Jefferson County, southeastern Nebraska [1990/12]

Journal

Bulletin of the United States Geological Survey

Issue

1915

Page number

30

Year

1990

Parent Taxon

[Order] Illiciales

Fossil Status

leaves

Type

Longstrethia varidentata

Diagnosis

Lamina very narrow elliptic to oblong; petiolar region poorly differentiated from the lamina; margin ranging from entire to coarsely toothed. Primary venation pinnate. Secondary venation ranging from brochidodromous, with strongly flattened brochidodromous loops, to pinnate with an intramarginal vein; secondary veins numerous, decurrent, irregular in course and spacing. Intersecondary veins present, branching into tertiary veins. Tertiary venation irregularly reticulate, enclosing areas of variable shape. Higher order venation not present or poorly developed. Cuticle with well-developed flanges. Guard cell pair broad-elliptic to circular, over 30 microns long; T -pieces present at the stomatal poles; each guard cell with a C-shaped lamellar cuticular thickening. Subsidiary cell arrangement predominantly laterocytic, sometimes also with polar subsidiary cells. Epidermal secretory cells present, each consisting of an isodiametric, polygonal cell surrounded by larger but several scarcely modified cells.