Huperzia serrata(Thunb.) Trevis.

toothed clubmoss

WFO wfo-0001125374 Accepted WFO 2026-06 8 photographs CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Huperzia serrata, photographed by Timur Kalininsky
fig. a Timur Kalininsky, CC BY 4.0 / 2022-04-21 / obs. 198478298

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

The specimen a real sheet, in a real collection

Herbarium
Smithsonian, US National Herbarium
Accession
US 3619212
Filed as
Huperzia serrata (Thunb.) Trevis.
Det. by
Puttock, C. F.
Collected
C. N. Forbes 1910-05
Origin
US
The sheet
View the digitised specimen (CC0 1.0)

A real pressed plant, in a real collection, under the accession number above. Not an illustration of one. The holding institution does not serve this sheet’s image to third parties, so there is no photograph here. The record is real and the link goes to it. Where we hold no openly licensed sheet for a species this section is simply absent, and where a sheet never recorded who determined it, that field stays empty rather than being filled in. Roughly half of all herbarium sheets never recorded a determiner, which is ordinary.

Native range 13 botanical countries

Regions where Huperzia serrata is native: Japan, Khabarovsk, Korea, Kuril Is., Manchuria, Nansei-shoto, Primorye, Sakhalin, Mexico Northeast, Mexico Southwest, Hawaii, Cuba, Haiti JapanKhabarovskManchuriaPrimoryeSakhalinMexico NortheastMexico SouthwestHawaiiCubaHaiti KoreaNansei-shoto
Native distribution of Huperzia serrata, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows. Regions too small to draw at this scale are marked with a dot.
RegionTDWG codeContinent
Japan JAP ASIA-TEMPERATE
Khabarovsk KHA
Korea KOR
Kuril Is. KUR
Manchuria CHM
Nansei-shoto NNS
Primorye PRM
Sakhalin SAK
Mexico Northeast MXE NORTHERN AMERICA
Mexico Southwest MXS
Cuba CUB SOUTHERN AMERICA
Haiti HAI
Hawaii HAW PACIFIC

Not drawn on the map: Kuril Is.. We hold no public-domain boundary for this region, so it is listed rather than guessed at.

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Where it actually grows measured, from 95 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -23.3 °C -2.0 °C 15.8 °C
Warmest month, mean daily high 16.6 °C 24.0 °C 29.5 °C
Annual rainfall 897 mm 1,884 mm 3,409 mm
Rainfall in the driest quarter 61 mm 225 mm 664 mm

It is found where winters are severely cold. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 95 research-grade observations of Huperzia serrata that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.

This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one.

Also published as 13 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Huperzia selago var. serrata (Thunb.) Á.Löve & D.Löve
  • Huperzia serrata (Thunb.) Rothm.
  • Huperzia serrata f. intermedia (Nakai) Ching
  • Huperzia serrata var. intermedia (Nakai) Satou
  • Huperzia serrata var. paucidentata (Sugim.) Satou
  • Lycopodium serratum Thunb.
  • Lycopodium serratum f. intermedium Nakai
  • Lycopodium serratum var. thunbergii Makino
  • Plananthus serratus (Thunb.) P.Beauv.
  • Urostachys sachalinensis (Nessel) Herter
  • Urostachys serratus (Thunb.) Herter ex Nessel
  • Urostachys serratus (Thunb.) Herter
  • Urostachys serratus var. sachalinensis Nessel

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
  4. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.