''Hamatophyton'' is a genus of the extinct

Sphenophyllales Sphenophyllales is an extinct order of articulate land plants and a sister group to the present-day Equisetales ( horsetails). They are fossils dating from the Devonian to the Triassic. They were common during the Late Pennsylvanian to Early ...

horsetails. Unique to this genus among other Sphenophyllales is its lack of secondary xylem around the tips of the primary xylem arms. One of its species has also been placed in the genus ''Sphenophyllostachys'', which is regarded as a

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of '' Bowmanites'' by the

Interim Register of Marine and Nonmarine Genera The Interim Register of Marine and Nonmarine Genera (IRMNG) is a taxonomic database which attempts to cover published genus names for all domains of life (also including subgenera in zoology), from 1758 in zoology (1753 in botany) up to the pre ...

Taxonomy

The taxonomic status of the genus and its possible species is confused. , the International Fossil Plant Names Index regards ''Hamatophyton'' as an invalid name since its publication in 1974 because the species name on which the genus was based, ''Hamatophyton verticillatum'', is invalid as no

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was designated. In 1991, ''Hamatophyton verticillatum'' was transferred to the genus ''Sphenophyllostachys'' as ''Sphenophyllostachys verticillata'', but since the basionym was invalid, this name is also invalid. Both species that have been placed in ''Hamatophyton'' are also treated as

synonymous A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

with '' Rotafolia songziensis''.

Species

*†'' Hamatophyton verticillatum'' L.-H. Deng, X.-X. Li, Z.-Y. Zhou, R. Xu, J.-N. Zhu, nom. inval., syns ''Sphenophyllostachys verticillata'', ''Rotafolia songziensis'' *†''Hamatophyton yiduense'' (G.-X. Chen) S.-N. Feng, nom. inval., syns ''Sphenophyllum yiduense'', ''Rotafolia songziensis''

References

Horsetails Late Devonian plants Mississippian plants Prehistoric plant genera Late Devonian first appearances Mississippian extinctions Famennian life Tournaisian life Famennian genus first appearances {{carboniferous-plant-stub