Sporangiostrobus langfordii Chaloner

Plant Fossil Names Registry Number: PFN000063

Act LSID: urn:lsid:plantfossilnames.org:act:63

Author: W. G. Chaloner

Rank: species

Reference: Chaloner, W. G. (1956): On Sporangiostrobus langfordi sp. nov., a New Fossil Lycopod Cone from Illinois. – The American Midland Naturalist 55(2): 437–442., link

Page of description: 439

Illustrations or figures: figs 1, 3

Types

Original diagnosis/description

Cone of unknown length, at least 6 cm long and 4.5 cm wide, tapering rather abruptly at the apex. Axis forming about 3/5 of the cone diameter, 2.8 cm at the widest part. Sporangia 5-6 mm wide (measured tangentially to the cone), 5-6 mm high (measured parallel to the cone axis), up to 10 mm long (measured radially to the cone axis) with a rounded-truncate distal end. Apparently borne on the axis in the axils of the bracts, in alternating whorls (or in a spiral arrangement in which the two parastichies appear to be equally inclined to the axis). Sporangia dontaining only megaspores, agreeing with Triletes superbus Bartlett. Body of the megaspore spheroidal, 1740-2230μ in diameter (mean of 8 measured, 1970μ), with a broad equatorial flange formed by anastomosing outgrowths, 610-920μ wide, broadest opposite the triradiate ridges. Sporewall 50-55μ thick. Hair-like outgrowths 10-15μ wide distributed over the spore body, concentrated mainly in the equatorial region, where they merge with the flange, diminishing in length and density towards the distal pole; absent or rare on the contact faces. Triradiate ridges relatively tall (up to 760μ high) with vertical plications and striae, extending to the equator of the spore body.

Stratigraphy

Carboniferous, Pennsylvanian
presumably from the shale above the No. 2 Coal, Carbondale formation

Locality

United States
Mazon Creek, vicinity of Coal City, Illinois