''Celatheca'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of extinct plants of the Early Devonian (Pragian, around ). Fossils were first found in the Posongchong Formation of eastern Yunnan, China. The leafless stems (axes) divided dichotomously but unequally so that one branch formed more of a 'main' stem and the other a side branch system. Side branches which did not bear

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

-forming organs or

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 cy ...

divided two or three times further, ending in tips which curled back on themselves. Side branches bearing sporangia ultimately divided to produce a group of four sporangia, each with an outer leaf-like

bract In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...

which folded around the sporangium. ''Celatheca'' resembles the Australian fossil '' Yarravia''.

References

Early Devonian plants Prehistoric plant genera {{devonian-plant-stub