This is Mazon Monday post #301.  What’s your favorite Mazon Creek fossil?  Tell us at email:esconi.info@gmail.com.

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Cordaianthus ovatus is thought to be the fertile structure for Cordaites borassifolius (see Mazon Monday #299), an extinct genus of early gymnosperms. Cordaites probably grew to more than 100 feet tall in swampy conditions, forming forests similar to modern day mangroves.

Cordaianthus ovatus was originally named Schutzia bracteata by Leo Lesquereux in 1870. He later renamed it to Cordaianthus ovatus in 1880. Lesquereux, a Swiss-born bryologist, is widely considered one of the fathers of American paleobotany. One of his best known works is the book “Atlas to the Coal Flora of Pennsylvania and the Carboniferous Formation throughout the United States”, which is a three-volume publication that was the standard for U.S. carboniferous flora for many years.

Jack Wittry discusses Cordaianthus ovatus on page 222 of his book “A Comprehensive Guide to the Fossil Flora of Mazon Creek”.

Cordaianthus ovatus (Lesquereux) White, 1899

1870. Schutzia bracteata Lesquereux: p. 427, pl. 21, figs. 6-9
1879. Cordaianthus gemmifer Grand’Eury; Lesquereux: pl. 76, fig. 5
1880. Cordaianthus ovatus Lesquereux: p. 545
1899. Cordaianthus ovatus Lesquereux; White: p. 262, pl. 72, figs. 1, 2
1925. Cordaianthus gemmifer Grand’Eury; Noé: p. 108, pl. 45, fig. 3
1958. Cordaianthus gemifer; Langford: p. 121, fig. 226
1979. Cordaianthus; Janssen: p. 74, fig. 57

DESCRIPTION: These compound structures are made of opposite-arranged, spine-like sterile bracts attached to a smooth axis. The fertile structures are sessile and attached to the axis at the junction of the sterile bracts. The fertile structures are conical and truncate at the apex when open. They have varying numbers of overlapping. tightly adpressed or slightly open scales, depending on their age.

REMARKS: Cordaianthus ovatus is uncommon. White was able to clarify this taxon when he determined that forms figured by Lesquereux of both Cordaianthus gemmifer and Cordaianthus ovatus could be seen associated with the same plant, and were actually the same thing. The application of the name Cordaianthus gemmifer to North American forms is in doubt. A source of confusion connected with this is that White found Cordaianthus ovatus associated with what he called Cordaites communis. The problem is that White’s interpretation of Lesquereux’s Cordaites communis appears to be incorrect and should not have been applied to the Cordaites form he described. The Cordaites he was describing as C. communis seems conspecific to the Mazon Creek form referred here, and also by Lesquereux, as Cordaites borassifolius. What this means, though never directly observed in the Mazon Creek flora, is that a case can be made that Cordaianthus ovatus is likely the fertile shoot borne from the plant as Cordaites borassifolius.

Specimens

Field Museum K11-2027. This specimen was collected by Jim and Sylvia Konecny on May 16th, 1970 from Dresden Lakes (Pit 10), Lorenzo, Illinois.

Field Museum K11-2035. This specimen was collected by by Jim and Sylvia Konecny on May 17th, 1969 from Meneoka, (Pit 5), Braidwood, Illinois.