''Eohostimella heathana'' is an early, probably terrestrial, "plant" known from

compression fossil A compression fossil is a fossil preserved in sedimentary rock that has undergone physical compression. While it is uncommon to find animals preserved as good compression fossils, it is very common to find plants preserved this way. The reason f ...

s of Early Silurian age (Llandovery, around , p. 4). The chemistry of its fossils is similar to that of fossilised vascular plants, rather than algae. Its anatomy constitutes upright, cylindrical tubes, with a thickened outer

cortex Cortex or cortical may refer to: Biology * Cortex (anatomy), the outermost layer of an organ ** Cerebral cortex, the outer layer of the vertebrate cerebrum, part of which is the ''forebrain'' *** Motor cortex, the regions of the cerebral cortex i ...

, which might have contained traces of lignin or a similar compound, even though no

tracheid A tracheid is a long and tapered lignified cell in the xylem of vascular plants. It is a type of conductive cell called a tracheary element. Angiosperms use another type of tracheary element, called vessel elements, to transport water through th ...

s or similar vessels have been found; the lignin-like compound was presumably associated with its thick outer cortex. It branched dichotomously and might have borne small spines. It was probably affiliated with the

rhyniophyte The rhyniophytes are a group of extinct early vascular plants that are considered to be similar to the genus '' Rhynia'', found in the Early Devonian (around ). Sources vary in the name and rank used for this group, some treating it as the class ...

References

Prehistoric plant genera Silurian life Prehistoric plants of North America {{silurian-plant-stub