This is Mazon Monday post #69. What's your favorite Mazon Creek fossil? Tell us at email:[email protected].
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Cyperites bicarinatus is a common plant found in the Mazon Creek fossil biota. They are grass-like with a rounded attachment at one end and a point at the other. The Field Museum has a specimen that is about 40 cm long, but can be much longer, maybe as much as a meter. This plant was the sterile leaves for the Lycopsida, which were giant club mosses. John Lindley and William Hutton described C. bicarinatus back in 1832. They wrote a series 3 volumes which described the fossil flora of Great Britain called "The Fossil Flora of Great Britain: of Figures and Descriptions of the Vegetable Remains Found in a Fossil State in this Country".
John Lindley (1799 - 1865) was an English botanist. He was employed early in his career as the assistant librarian to Sir Joseph Banks. In 1822 he became the Assistant Secretary to the Royal Horticultural Society and from 1829 to 1860 he was first Professor of Botany at the University of London and lecturer in botany to the Apothecaries’ Company (1836). He then became a Professor of Botany at Cambridge University. His Report to Treasury and Parliament in 1838 led to the preservation of the Royal Garden at Kew. He described the plants of Mitchell's expeditions to Australia (1838) and an Appendix to the Botanical Register (1839) described plants of the Swan River Colony, Western Australia. His pioneering three-volume work of palaeobotany of England, was first published between 1831 and 1837. The work catalogues almost 300 species of fossil plants from the Pleistocene to the Carboniferous period. The geologist and paleontologist William Hutton (1797-1860), was responsible for collecting the fossil specimens on which the plates were based.
The Lycopsida have a nice description by Jack Wittry in "A Comprehensive Guide to the Fossil Flora of Mazon Creek" on page 4. By the way, that book is the essential guide to Mazon Creek plants for any serious collector. If you don't have it, what are you waiting for? ESCONI sells them!
Lycopsida: Ancient Club Mosses
The largest plants of the Mazon Creek flora were the arborescent lycophytes. Up to 80 percent of the North American and European Westphalian coals typically consists of biomass derived from the bark of arborescent lycophytes. From research using spore counts (Peppers and Pfefferkorn, 1970), this also appears to be the case in the Colchester No. 2 Coal which lays directly under the Francis Creek Shale in which the Mazon Creek fossils were formed.
Arborescent lycophyte taxa could grow to a maximum height of 10 to 50 meters, with a trunk width from 10 centimeters to over 2 meters across at the base. Their lifespans measured in centuries, with 400 years being the likely baseline for most species (Boyce and DiMichele, 2016). During the growth years, the plant appeared pole-like in form and did not branch or reproduce until fully grown. The lycophytes occupied the ever-wet areas of flood basins, necessitating the adaptation of spreading roots which grew laterally around the trunk, thus forming a wide and stable base needed in the wet soil. The feature that separates the lycophytes from modern trees is that the former contained very little wood; instead, thick bark strengthened the trunk. They did not reproduce by seeds as modern trees do, but produced microspores and megaspores in cones.
The lycopsid tree forms in the Mazon Creek flora fall into nine generic types: Sigillaria, Asolanus, Omphalophloios, Sublepidophloios, Synchysidendron, Diaphorodendron, Bergeria, Bothrodendron, and Lepidodendron. These names are the genera names used for the outer bark from these trees as well. All of their root-like support branches are named Stigmaria. The cones are called Lepidostrobus except for those borne on Sigillaria, which are called Sigillariostrobus. All of the individual cone bracts are named Lepidostrobophyllum. The long, thin, grass-like leaves are called Cyperites. The previous, now invalid, name for these leaves was Lepidophyllum. It was replaced when it was found that the name was already in use for an extant flowering plant and could no longer be used due to the rules governing name priority. It is not always possible to place the plant's parts with the parent tree. Generic names are often just a convenience that lump similar species together regardless of what the original plant may have been.
Apart from arborescent forms, there are poorly understood diminutive forms in the family Chaloneriaceae. They were unbranched and grew outside the ever-wet habitats in the flood basin. All of the arborescent and diminutive forms are now extinct.
Wittry's description and remarks are found on page 5 and 6.
Cyperites bicarinatus Lindley & Hutton, 1832
1832. Cyperites bicarinatus Lindley and Hutton: p. 123, pl. 43, figs. 1, 2
1966. Cyperites bicarinatus Lindley and Hutton; Crookall: p. 534, pl. 105, fig. 7; text-fig. 153
DESCRIPTION: These forms are slender, long, grass-like leaves, which are widest at the base and gently taper to a sharp apex. In cross section, they may be round or triangular over their length. The base is straight and seldom shows any indication of the leaf cushion shape. Running down the center of the leaf is a wide band accompanied by two or sometimes three grooves along each side (see Fig. 9). A center vein has been noted, but is often missing. All veins run down the entire long axis of the leaf. The margins are entire. The leaves may be from as little as 1 cm to nearly 1 m in length. The apex is pointed and the base is slightly expanded.
REMARKS: Cyperites bicarinatus is very common, but this can be quite variable depending on the collecting site. Leaves of this type were borne by all of the arborescent lycophytes. The name stays the same regardless of the parent plant. This is a matter of necessity as the leaves of all were very similar and there is no way to separate them after they had become detached from the parent tree. Also, the number and character of the ridges preserved on a leaf vary according to the type of preservation and whether the top or bottom surface is preserved. This variability makes it difficult to reliably split individual leaves into species. The figures shown here display the great variability in leaf size, from the small and thin leaves on a terminal shoot in Fig. 2, to a single, very large example shown in Fig. 1.
The generic name Lepidophylloides was proposed in 1958 to replace Brongniart's invalid name, Lepidophyllum. Both names were used to describe the leaf-like fertile bracts of lycopsid cones as well the sterile leaves of the branches and trunk. The cone bracts are now placed in a separate genus called Lepidostrobophyllum. The generic name Cyperites now replaces Lepidophylloides and Lepidophyllum for the sterile leaves of arborescent lycophytes. See Lepidostrobophyllum.
Cyperites bicarinatus is most often found singularly, but also commonly found detached in clusters with the apices seemingly united and their bases spread out. The reason for this backward arrangement is uncertain, but probably due to hydrostatic tension. Leaves found still attached to the parent plant radiate from it in the usual way (see Fig. 8).
Specimens
This specimen was contributed by ESCONI member Chris Berg. Look for the prominent ridge down the middle.
Notice how the next two specimens are 3 dimensional.
