''Tortilicaulis'' is a moss-like

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...

known from

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s recovered from southern Britain, spanning the Silurian-Devonian boundary (around ). Originally recovered from the Downtonian of the Welsh borderlands, ''Tortilicaulis'' has since been recovered in the famous Ludlow Lane locality. Whilst it is generally accepted that ''Tortilicaulis'' was moss-like, it has not yet been recovered in a sufficiently good state of preservation to allow the detailed study necessary to firmly assign it to a taxonomic group. Fossils consist of an elongate apical sporangium (spore-forming organ), which may be branched, with spiralled walls attached to an undivided stalk that is also twisted. Unusually for plants of its time, spores of ''Tortilicaulis'' were covered all over with small granules. The initial suspicions of its describer, Dianne Edwards, were that it was a

bryophyte The Bryophyta s.l. are a proposed taxonomic division containing three groups of non-vascular land plants (embryophytes): the liverworts, hornworts and mosses. Bryophyta s.s. consists of the mosses only. They are characteristically limited in s ...

, and comparisons have been made with several groups. A potential association with the moss '' Takakia'' is supported by features of the

sporangia A sporangium (; from Late Latin, ) is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. Virtually all plants, fungi, and many other lineages form sporangia at some point in their life cyc ...

, such as the elongate shape, unusual twisting, and terminal position of the

. As the sporangia of ''Tortilicaulis'' are branched, cladistic analysis suggests that the genus may instead belong to the

Horneophytopsida The Horneophytopsida, informally called horneophytes, are a class of extinct plants which consisted of branched stems without leaves, true roots or vascular tissue, found from the Late Silurian to the Early Devonian (around ). They are the sim ...

, a class of the

polysporangiophyte Polysporangiophytes, also called polysporangiates or formally Polysporangiophyta, are plants in which the spore-bearing generation (sporophyte) has branching stems (axes) that bear sporangia. The name literally means 'many sporangia plant'. The cl ...

s, which unlike bryophytes, have branched stems bearing sporangia. Its precise nature and hence classification remains unclear., p. 165 For the cladogram, see the

article.

References

{{Taxonbar, from=Q7827290 Early Devonian plants Silurian plants Prehistoric plant genera Pridoli first appearances Early Devonian genus extinctions