''Runcaria heinzelinii'' is an
extinct
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
of
plant
Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...
from the
Middle Devonian
In the geological timescale, the Middle Devonian epoch (from 393.3 ± 1.2 million years ago to 382.7 ± 1.6 million years ago) occurred during the Devonian period, after the end of the Emsian age.
The Middle Devonian epoch is subdivided into two ...
of
Belgium
Belgium, officially the Kingdom of Belgium, is a country in Northwestern Europe. Situated in a coastal lowland region known as the Low Countries, it is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeas ...
. It is the only species classified under the genus ''Runcaria'',
named after
Jean de Heinzelin de Braucourt. 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 surrounded by a
cupule.
The
megasporangium 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, Exoskeleton, shell, germ or Peel (fruit), rind.
Etymology
The term is derived from ''integumentum'', which is Latin for "a coverin ...
, and there is an extension on the megasporangium that suggests an adaptation to
wind pollination. Thus, this fossil plant has all of the qualities of seed plants except for a solid
seed coat
In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be sown, which may include seed and husk or tuber. Seeds are the ...
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