''Runcaria heinzelinii'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

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 exclud ...

from the

Middle Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, wher ...

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...

. It is the only species classified under the genus ''Runcaria'', named after

Jean de Heinzelin de Braucourt Jean de Heinzelin de Braucourt (6 August 1920 – 4 November 1998) was a Belgian geologist who worked mainly in Africa. He worked at the universities of Ghent and Brussels. He gained international fame in 1960 when he discovered the Ishango Bo ...

. It was a precursor to seed plants, predating the earliest of the latter by about 20 million years. The fossil pieces of ''Runcaria heinzelinii'' that have been found are short branched stems that at their tips have a radially symmetrical

megasporangium 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 ...

surrounded by a

cupule A cupule is a small structure shaped like a cup, including: * In archeology, rock cupules are circular man-made hollows on the surface of a large rock or a rock slab ** On a smaller artifact they are called a cupstone. * In botany: the base of an ...

. The

has a multilobed

integument In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, shell, germ or rind. Etymology The term is derived from ''integumentum'', which is Latin for "a covering". In a transferred, or ...

, and there is an extension on the megasporangium that suggests an adaptation to

wind pollination Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including grasses, sedges, and rushes. Other common anemophilous plan ...

. Thus, this fossil plant has all of the qualities of seed plants except for a solid

seed coat A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm pl ...

and a system to guide the pollen to the ovulum. It sheds new light on how the seed may have evolved.

References

{{Taxonbar, from=Q7379686 Middle Devonian plants Transitional fossils Monotypic plant genera Prehistoric plant genera