I have recently been finding some trigonocarpus nuts in Ossett, West Yorkshire, UK and they are carboniferous in age. I was just wondering, what did trigonocarpus look like and how big was it? When I search trigonocarpus on the internet it just comes up with their fossil nuts and nothing else.
I would appriciate any answers on this one.
The pictures I have attached are fossil nuts which are the unmistakable shape of a trigonocarpus nuts. I found both of them.
We don't know.
Trigonocarpus is what we call a 'form genus'.
While with most genera we know what the complete organism looks like, or a significant part of it, there are several types of fossil where only part is known. In order to be able to discuss these fossils, they have been given names despite the uncertainty. Stigmaria is another 'form genus': it is the outer bark of large arborescent lycophytes. Similarly, Lepidophylloides is the leaves of arborescent lycophytes. See here for more - http://commonfossilsofoklahoma.snomnh.ou.edu/lycophytes.
If you like, you can think of fossils such as Trigonocarpus, Stigmaria and Lepidophylloides as pieces of a jigsaw; but one that we can't complete because we don't know how the pieces fit together.
In future, if some new technique is discovered, maybe we will be able to see the whole picture. Then, it would not be surprising if plants we call by one name now, eg. Lepidophylloides, were revealed to be several genera; or there might be a single new genus for which we currently use multiple 'form genus' names now.
There's a useful diagram part-way down this page, showing how various form genera refer to different parts of what may actually be one genus.
There is a very good, if old, discussion of Trigonocarpus (then called Trigonocarpon) here:
GEOLOGICAL SURVEY OF OHIO, VOL. 1. PART II.
PALÆONTOLOGY, SECTION III, DESCRIPTIONS OF FOSSIL PLANTS.
by J. S. NEWBERRY, 1873
See especially. pp.364-367.
If you read on, you will learn about particular 'species' of Trigonocarpus.
And then another form genus: Cardiocarpon (now Cardiocarpus). I think that will give you something else to look-out for...
Because you are very keen on Yorkshire fossils, be aware:
"The palaeobotany collections of the NHM are amongst the most important in museums worldwide in respect of their geographic, stratigraphic and historical range. They span the Archean to the Recent and in addition to plants contain cyanobacteria and fungi. The collection is particularly rich in fossils from the British coal measures, Yorkshire Jurassic, Eocene London Clay and some ex-British colonies such as Australia, S. Africa, India and Canada. Over 1100 type specimens are found in the collection of around 250,000 hand specimens and 30,000 slide preparations and fossils that range in size from microscopic cuticle preparations to a 15m long tree. The museum holds many palaeobotanical collections of historic importance, including those made by Charles Darwin, Marie Stopes, Captain Robert Falcon Scott, W.H. Lang, W.C. Williamson, W. Hemingway, F.W. Oliver, and D.H. Scott. The Seward Library contains a comprehensive set of reprints, monographs, general palaeobotany textbooks, theses and archives."
If you ever make a visit to the NHM, bear that in mind!
I am sure you can arrange to see some of those world-class collections.