Plenasium

Plenasium is a genus of ferns in the family Osmundaceae.^[1] It is recognized in the Pteridophyte Phylogeny Group classification of 2016 (PPG I),^[2] but kept within a more broadly circumscribed genus Osmunda by other sources.^[3] The genus is known from Early Cretaceous to present.^[4]

Plenasium Temporal range: Early Cretaceous–Recent PreꞒ Ꞓ O S D C P T J K Pg N
Plenasium vachellii (syn. Osmunda vachellii) in the Shing Mun Arboretum, Hong Kong
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Division:	Polypodiophyta
Class:	Polypodiopsida
Order:	Osmundales
Family:	Osmundaceae
Genus:	Plenasium C.Presl[1]
Type species
Plenasium banksiifolium (Presl) Presl
Species
See text
Synonyms
Aurealcaulis Tidwell & Parker 1987 ×Osmunasium Liu, Schuettpelz & H.Schneid. 2020

Taxonomy

As of October 2019^[update], the Checklist of Ferns and Lycophytes of the World accepted the following four species:^[1]

Phylogeny of Plenasium^[5][6]

	Plenasium angustifolium (Ching) A.E.Bobrov ×Osmunasium ×mildei (Christensen) Liu, Schuettpelz & H.Schneid. Plenasium vachellii (Hook.) C.Presl Plenasium banksiifolium (C.Presl) C.Presl Plenasium javanicum (Blume) C.Presl

The following fossil species are also accepted.^[4]

• †P. arnoldii (C.N.Mill. 1967) Bomfleur, Grimm & McLoughlin 2017
• †P. bransonii (Tidwell & Medlyn, 1991) Bomfleur, Grimm & McLoughlin 2017 (?Eocene: New Mexico, USA).
• †P. burgii (Tidwell & J.E.Skog, 2002) Bomfleur, Grimm & McLoughlin 2017 (Early Cretaceous: Nebraska, USA).
• †P. chandleri (Arnold 1952) Bomfleur, Grimm & McLoughlin
• †P. crossii (Tidwell & L.R.Parker, 1987) Bomfleur, Grimm & McLoughlin 2017 (Paleocene: Wyoming, USA).
• †P. dakotense (Tidwell & J.E.Skog, 2002) Bomfleur, Grimm & McLoughlin 2017 (Early Cretaceous: South Dakota, USA).
• †P. dowkeri (Carruthers 1870) Bomfleur, Grimm & McLoughlin 2017
• †P. moorei (Tidwell & Medlyn, 1991) Bomfleur, Grimm & McLoughlin 2017 (?Eocene: New Mexico, USA).
• †P. nebraskense (Tidwell & J.E.Skog, 2002) Bomfleur, Grimm & McLoughlin 2017 (Early Cretaceous: Nebraska, USA).
• †P. (Aurealcaulis) elegans Hiller et al. 2019 (Eocene, Vietnam)^[7]
• †P. (Plenasium) xiei Cheng et al. 2019 (Late Cretaceous, Northeastern China)^[8]