Huperzia

Huperzia is a genus of lycophyte plants, sometimes known as the firmosses or fir clubmosses; the Flora of North America calls them gemma fir-mosses.[2] This genus was originally included in the related genus Lycopodium, from which it differs in having undifferentiated sporangial leaves, and the sporangia not formed into apical cones. The common name firmoss, used for some of the north temperate species, refers to their superficial resemblance to branches of fir (Abies), a conifer. As of 2020, two very different circumscriptions of the genus were in use. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), Huperzia is one of three genera in the subfamily Huperzioideae of the family Lycopodiaceae. Most species in the subfamily are placed in the genus Phlegmariurus. Huperzia is left with about 25 species,[3] although not all have been formally transferred to other genera.[4] Other sources recognize only Huperzia, which then has about 340 species.[5]

Huperzia
Huperzia selago in Austria
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Lycophytes
Class: Lycopodiopsida
Order: Lycopodiales
Family: Lycopodiaceae
Subfamily: Huperzioideae
Genus: Huperzia
Bernh.[1]
Species

See text.

Morphology

The sporophytes of this genus have unbranched shoots that are generally upright and round in cross section. Horizontal stems are absent. The leaves are not borne in distinct ranks, and are usually somewhat lanceolate in shape. In some species, they vary in size according to the season in which they grow. Branchlets bearing gemmae – bud-like structures by which the plant reproduces asexually – occur among the leaves. The gemmae are triangular, with eight leaves in a constant pattern: four flattened into a plane and two large lateral leaves. The sporangia are kidney-shaped (reniform), occurring at the base of a leaf that is either unmodified or reduced. The roots are produced near the apex of shoots, and migrate downwards inside the cortex of the stem to emerge at soil level. The unbranched gametophytes are not photosynthetic, but rather subterranean and mycorrhizal.[2]

The Flora of North America distinguishes Huperzia from the epiphytic tropical genus Phlegmariurus on the basis of differences such as the former's complex and specialized shoots, the gemmae and the branchlets on which they are borne, and the unbranched gametophytes.[2]

Taxonomy

The genus Huperzia was created by Johann Jakob Bernhardi in 1801. Bernhardi separated Huperzia from Lycopodium. The type species is Lycopodium selago which became Huperzia selago.[1]

In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), Huperzia is placed in the subfamily Huperzioideae of the family Lycopodiaceae.[3] A phylogenetic study in 2016, employing both molecular and morphological data, concluded that either a one-genus or a three-genus division of the subfamily produced monophyletic taxa. The authors preferred the three-genus division, recognizing Huperzia, Phlegmariurus and Phylloglossum. Their preferred hypothesis for the relationships of the three genera was:[6]

Huperzioideae
 
 

Phylloglossum

 
 

Huperzia

 
 
 

Phlegmariurus

 
 

The majority of the species formerly placed in a broadly defined Huperzia belong in Phlegmariurus.[6] Earlier, the Flora of North America had also separated Huperzia from Phegmariurus.[2] However, Phlegmariurus is difficult to separate morphologically, and others have preferred the one-genus division of the subfamily.[7][5]

Species

The PPG I classification stated there were 25 species in the genus Huperzia.[3] As of September 2020, World Ferns listed 56 species, noting that "many species still need transfer into other split genera".[4]

  • Huperzia appalachiana Beitel & Mickel
  • Huperzia archboldiana (Nessel) Holub
  • Huperzia arunachalensis (D.D.Pant & P.S.Pandey) Fraser-Jenk.
  • Huperzia asiatica (Ching) N.Shrestha & X.C.Zhang
  • Huperzia australiana (Herter) Holub
  • Huperzia beccarii (Alderw.) Holub
  • Huperzia bucahwangensis Ching
  • Huperzia campestris (Alderw.) Holub
  • Huperzia chinensis (Christ) Ching
  • Huperzia chishuiensis X.Y.Wang & P.S.Wang
  • Huperzia continentalis Testo, A.Haines & A.V.Gilman
  • Huperzia crispata (Ching) Ching
  • Huperzia emeiensis (Ching & H.S.Kung) Ching & H.S.Kung
  • Huperzia erubescens (Brack.) Holub
  • Huperzia everettii (Herter) Holub
  • Huperzia fuegiana (Roiv.) Holub
  • Huperzia gedeana (Alderw.) Holub
  • Huperzia goliathensis (Alderw.) Holub
  • Huperzia haleakalae (Brack.) Holub
  • Huperzia herteriana (Kümmerle) T.Sen & U.Sen
  • Huperzia javanica (Sw.) Fraser-Jenk.
  • Huperzia jejuensis B.Y.Sun & J.Lim
  • Huperzia kangdingensis (Ching) Ching
  • Huperzia kunmingensis Ching
  • Huperzia laipoensis Ching
  • Huperzia lajouensis Ching
  • Huperzia leishanensis X.Y.Wang
  • Huperzia liangshanica (H.S.Kung) Ching & H.S.Kung
  • Huperzia lucidula (Michx.) Trevis.
  • Huperzia medogensis Ching & Y.X.Lin
  • Huperzia meghalaica Fraser-Jenk.
  • Huperzia miniata (Spring) Trevis.
  • Huperzia minima (Herter) Holub
  • Huperzia miyoshiana (Makino) Ching
  • Huperzia muscicola W.M.Chu
  • Huperzia nanchuanensis (Ching & H.S.Kung) Ching & H.S.Kung
  • Huperzia nanlingensis Shrestha, F.W.Xing, X.P.Qi, Y.H.Yan & X.C.Zhang
  • Huperzia occidentalis (Clute) Kartesz & Gandhi
  • Huperzia petrovii Sipliv.
  • Huperzia porophila (F.E.Lloyd & Underw.) Holub
  • Huperzia quasipolytrichoides (Hayata) Ching
  • Huperzia rubicaulis S.K.Wu & X.Cheng
  • Huperzia rubricaulis (Alderw.) Holub
  • Huperzia saururoides (Bory & D'Urv.) Rothm.
  • Huperzia selago (L.) Bernh. (including H. selago subsp. appressa - Appalachian firmoss)
  • Huperzia serrata (Thunb.) Trevis.
  • Huperzia shresthae Fraser-Jenk.
  • Huperzia somae (Hayata) Ching
  • Huperzia sprengeri (Nessel) Holub
  • Huperzia suberecta (Lowe) Tardieu
  • Huperzia sumatrana (Alderw.) Holub
  • Huperzia sutchueniana (Herter) Ching
  • Huperzia tibetica (Ching) Ching
  • Huperzia yakusimensis (Herter) Holub
  • Huperzia zollingeri (Herter) Holub

Former species

Many species formerly placed in Huperzia have been transferred to the genus Phlegmariurus, including the following (synonyms from World Ferns):

Distribution and habitat

As circumscribed in the PPG I classification, Huperzia is distributed in temperate, arctic and alpine habitats, including mountains in tropical Asia.[4] Its species are terrestrial or grow on rocks.[2] Phlegmariurus is epiphytic,[2] and has a worldwide tropical distribution,[7] so when Huperzia is defined broadly to include all three genera of the subfamily Huperzioideae, it has an almost worldwide distribution, absent mainly in North Africa, the Arabian Peninsula and Western Asia.[5]

References
  1. "Huperzia Bernh.", The International Plant Names Index, retrieved 2020-09-16
  2. Wagner Jr., Warren H. & Beitel, Joseph M., "Huperzia", in Flora of North America Editorial Committee (ed.), Flora of North America (online), eFloras.org, retrieved 2020-09-16
  3. PPG I (2016), "A community-derived classification for extant lycophytes and ferns", Journal of Systematics and Evolution, 54 (6): 563–603, doi:10.1111/jse.12229, S2CID 39980610
  4. Hassler, Michael & Schmitt, Bernd (April 2020), "Huperzia", World Ferns, 8.30, retrieved 2020-09-16
  5. "Huperzia Bernh.", Plants of the World Online, Royal Botanic Gardens, Kew, retrieved 2020-09-15
  6. Field, Ashley R.; Testo, Weston; Bostock, Peter D.; Holtum, Joseph A. M. & Waycott, Michelle (2016), "Molecular phylogenetics and the morphology of the Lycopodiaceae subfamily Huperzioideae supports three genera: Huperzia, Phlegmariurus and Phylloglossum", Molecular Phylogenetics and Evolution, 94 (Pt B): 635–657, doi:10.1016/j.ympev.2015.09.024, PMID 26493224
  7. Hassler, Michael & Schmitt, Bernd (April 2020), "Phlegmariurus", World Ferns, 8.30, retrieved 2020-09-16
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