Nematothallus is a genus of early land plant known only from the fossil record. It was first described by Lang in 1933^[2], who envisioned it being a thallose plant with tubular features and sporophytes, covered by a cuticle which preserved impressions of the underlying cells. He had found abundant disaggregated remains of all three features, none of which were connected to another, leaving his reconstruction of the phytodebris as parts of a single organism highly conjectural. The Silurian is a major division of the geologic timescale that extends from the end of the Ordovician period, about 443. ... Artists illustration of a Devonian scene. ... Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ... For other uses, see Plant (disambiguation). ... For other uses, see Genus (disambiguation). ... For other uses, see Fossil (disambiguation). ... Thallus is an undifferentiated vegetative tissue (without specialization of function) of some non-mobile organisms, which were previously known as the thallophytes. ...

Further work failed to draw together aspects of the organism: Edwards (1982) and Edwards and Rose (1984) both provided thorough descriptions of the cuticular aspects of the plants, while Pratt et al. (1978) and Niklas and Smocovitis (1983) focused on the anatomy of the tubes.

The lack of a clear definition of Nematothallus has led to it being used as a wastebasket form taxon, with all manner of tubes and cell-patterned cuticles from around the Silurian being dubbed "Nematophytic" more as a statement of ignorance than as a scientifically meaningful statement. Wastebasket taxon (also called a wastebin taxon or dustbin taxon) is a term used in taxonomic circles to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. ...

The genus was later formalised by Strother,^[1] who discovered better preserved and more complete specimens in Pennsylvania, America.^[3] Capital Harrisburg Largest city Philadelphia Area  Ranked 33rd  - Total 46,055 sq mi (119,283 km²)  - Width 280 miles (455 km)  - Length 160 miles (255 km)  - % water 2. ...

Linnean taxonomy struggles to accommodate most fossil groups, as they tend to form stem groups to modern taxa. Thus despite Strother's attempts to formalise the nomenclature of Nematothalli, the hierarchy of class, order and family are better thought of as a stem group to the embryophytes (modern land plants), with the green algæ a stem group to the Nematophytes in turn. Linnaean taxonomy classifies living things into a hierarchy, originally starting with kingdoms. ... In palaeontology, a stem group is a systematic grouping that is required to accommodate fossils in the classification of organisms. ... Divisions Non-vascular land plants (bryophytes) Marchantiophyta - liverworts Anthocerotophyta - hornworts Bryophyta - mosses †Horneophytopsida Vascular plants (tracheophytes) †Rhyniophyta—rhyniophytes †Zosterophyllophyta—zosterophylls Lycopodiophyta—clubmosses †Trimerophytophyta—trimerophytes Pteridophyta - ferns and horsetails Ophioglossophyta - adders-tongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants The embryophytes...

References

McGregor and Narbonne (1978): "Upper Silurian trilete spores and other microfossils from the Read Bay Formation, Cornwallis Island, Canadian Arctic" Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 244th day of the year (245th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 244th day of the year (245th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 244th day of the year (245th in leap years) in the Gregorian calendar. ...