Botryopteris cratis

Name

Botryopteris cratis

Rank

Species

Generic Name

[Genus] Botryopteris

Authors (Pub.)

Millay M. A. Taylor T. N.  

Publication

An Unusual Botryopterid Sporangial Aggregation from the Middle Pennsylvanian of North America [1980/6]

Journal

American Journal of Botany

Volume

67

Issue

5

Page number

768

Year

1980

Parent Taxon

[Genus] Botryopteris

Fossil Status

foliage (fertile)

Stratigraphy

Moscovian

Location

Sahara Coal Company, mine No. 6 near Carrier Mills, Illinois, USA

Paleoregion

Laurussia (Laurentia)

Data for Holotypus

Repository Number

7734-7834 (coal ball 2089)

Diagnosis

Paleozoic fern; stem radial, up to 3.0 mm in diam, protostelic with wholly tracheidal xylem, centrarch with protoxylem strands associated with leaf trace departure, metaxylem elements with scalariform, reticulate or opposite, elongate-oval to oval, bordered pitting; cortex three layered, wide inner zone of thick-walled axially elongate parenchyma, some cells enlarged containing unlayered or concentrically layered contents, wide middle zone of thin-walled cells, outer cortical zone narrow, of thick-walled rectangular cells in radial files, stem surface with small mounds of tissue and uniseriate multicellular hairs arising from multicellular bases. Stem and petiolar trace with xylem sheath of cells containing dark contents. Foliar members with bilateral symmetry, up to 3.0 mm in diam, adaxial surface concave or flat, xylem bundle in one or two parts, in transverse section consists of a larger crescent-shaped bar with protoxylem aref!S at tips, and central adaxial area of xylem resembling a triangle with one or two protoxylem areas, or a crescent with two protoxylem areas; adventitious stems originate from middle xylem arm of frond members; protoxylem strand of middle xylem arm sometimes involved in lateral trace production; metaxylem tracheids with multiseriate, alternate, oval bordered pits; cortex divided into inner parenchymatous zone and outer fiber zone, fiber zone proportionately wider in small frond members and eccentrically developed in fertile axes, epidermis of small empty cells. Fertile frond members pinnately branched throughout, surrounding a mass of sporangia; frond members oval to crescent-shaped in transverse section, xylem bundle with 1-3 adaxial protoxylem strands. Sporangia spherical (0.57 mm diam), borne on pinnae less than 0.5 mm diam, pedicel short, annulus lateral-horizontal, subequatorial, two cells high, extending approx. one-half circumference. Spherical to oval spores, 55-100 μm maximum diam (average 88 x 78 μm), with symmetrical trilete suture and raised straight commissure; ornamentation of isolated grana and pila, and short and long, curved to sinuous ridges 0.8-2.5 μm wide, separated by grooves averaging 1.5 μm wide; thin outer, separable wall layer covering spores.