Pandemophyllum

Name

Pandemophyllum

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

21

Year

1990

Parent Taxon

[Order] Laurales

Fossil Status

leaves

Type

Pandemophyllum kvacekii

Diagnosis

Leaf simple; demarcation between petiole and blade indistinct; margin entire and with structural reinforcement. Primary venation pinnate. Secondary venation festooned brochidodromous but forming flattened brochidodromous arches in at least the apical quarter of the lamina; strong basilaminar secondary veins absent but with a thin pair of secondary veins present near the base of the lamina. Intersecondary veins present in some intercostal regions, branching to form tertiary veins. Tertiary venation unbranched to reticulate, often with a ramified component, irregularly transverse; tertiary veins irregularly spaced, enclosing regions no more than 2-3 times as long as wide. Quaternary venation unbranched to reticulate and ramified; quaternary veins non-orthogonally rooted, often irregularly transverse to the tertiary veins, irregularly spaced, tending to be admedially branched. Cuticle of medium thickness, easy to prepare, flanges well developed. Guard cells typically spindle shaped, with well-developed lamellar thickenings along the boundary with the inner pair of subsidiary cells, strong lamellar thickenings developed over the inner pair of subsidiary cells in some species, lamellar cuticular thickenings often appearing to "float" in the stomatal complex under light microscopy. Stomatal complex brachyparacytic to amphibrachyparacytic. Trichome bases, when present, consisting of an angular to rounded pore with a heavily cutinized margin and several adjacent cells that often are radially oriented.