''Archaefructus'' is an extinct genus of herbaceous aquatic

seed plant A spermatophyte (; ), also known as phanerogam (taxon Phanerogamae) or phaenogam (taxon Phaenogamae), is any plant that produces seeds, hence the alternative name seed plant. Spermatophytes are a subset of the embryophytes or land plants. They inc ...

s with three known species.

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 ...

material assigned to this genus originates from the

Yixian Formation The Yixian Formation (; formerly transcribed as Yihsien Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the late Barremian and early Aptian stages of the Early Cretaceous. It is known for its exq ...

in northeastern China, originally dated as late

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

but now thought to be approximately 125 million years old, or early

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

in age. Even with its revised age, ''Archaefructus'' has been proposed to be one of the earliest known genera of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s. Because of its age, lack of

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coine ...

s and petals, and the fact that its reproductive organs (

carpel Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) '' pistils' ...

s and stamens), are produced on an elongate stem rather than condensed into a flower as in modern angiosperms, Archaefructaceae has been proposed as a new basal angiosperm family. An alternative interpretation of the same fossil, however, interprets the elongate stem as an inflorescence rather than a flower, with staminate (male) flowers below and pistillate (female) flower above. The discovery of ''Archaefructus eoflora''Ji, Q., H. Li, L.M. Bowe, Y. Liu & D.W. Taylor 2004. ''Acta Geologica Sinica'' 78(4): 883–896. supports this interpretation, because a bisexual flower is present in the region between staminate and pistillate organs. If this interpretation is correct, ''Archaefructus'' may not be basal within the angiosperms, rather it may be close to the

Nymphaeales The Nymphaeales are an order of flowering plants, consisting of three families of aquatic plants, the Hydatellaceae, the Cabombaceae, and the Nymphaeaceae (water lilies). It is one of the three orders of basal angiosperms, an early-diverging ...

or the basal

eudicots The eudicots, Eudicotidae, or eudicotyledons are a clade of flowering plants mainly characterized by having two seed leaves upon germination. The term derives from Dicotyledons. Traditionally they were called tricolpates or non-magnoliid dicots ...

References

External links

Virtual Fossil Collection: ''Archaefructus''
* Mark Norell
Unearthing the Dragon
, p. 103 and 106 (Archaefructus misspelled as Archaeofructus) {{Taxonbar, from=Q137507 Prehistoric angiosperm genera Enigmatic angiosperm taxa Early Cretaceous plants Cretaceous angiosperms

See also

References

External links