Triadenum

Triadenum
Triadenum virginicum
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Malpighiales
Family:	Hypericaceae
Tribe:	Cratoxyleae
Genus:	Triadenum Raf.
Type species
T. fraseri (Spach) Gleason
Synonyms [1]
GardeniaColden HypericumL. sect. ElodeaChoisy

Triadenum, known as marsh St. John's worts, ^[2] is a small genus of flowering plants in the family Hypericaceae. The genus is characterized by opposite, blunt-tipped leaves and pink flowers with 9 stamens. They are distributed in North America and eastern Asia.

Acceptance of this genus is varied. Kew's Plants of the World Online ^[3] and the Database of Vascular Plants of Canada (VASCAN) ^[4] treat it as a junior synonym of Hypericum and the Flora of North America ^[1] and Flora of China ^[5] treat it as separate. The situation arises from B. R. Ruhfel et al. (2011)'s genetic study describing Triadenum as subsumed under Hypericum and later genetic results disagreeing with this assessment. ^[6] Under Hypericum, the species are mostly treated as the section Hypericum sect. Elodea. ^[7]

Species

Triadenum contains the following 6 species according to Flora of North America and Flora of China: ^{[1] [5]}

• Triadenum breviflorum (Wall.)
• Triadenum fraseri (Spach) Gleason
• Triadenum japonicum (Thunb.)
• Triadenum tubulosum (Walter) Gleason
• Triadenum virginicum (L.) Raf.
• Triadenum walteri (J.F.Gmel.) Gleason

References

1. "Triadenum in Flora of North America @ efloras.org". www.efloras.org. Retrieved 2021-12-15.
2. NRCS. "Triadenum". PLANTS Database. United States Department of Agriculture (USDA). Retrieved 14 December 2015.
3. "Triadenum Raf". Plants of the World Online.
4. "Triadenum". VASCAN. Retrieved 17 June 2022.
5. "Triadenum in Flora of China @ efloras.org". www.efloras.org.
6. Robson, N. K. (2021). "Studies in the genus Hypericum L.(Hypericaceae) 9. Addenda, corrigenda, keys, lists and general discussion" . Phytotaxa. 72: 1–111. doi:10.11646/phytotaxa.72.1.1.
7. Robson, Norman K.B. (11 April 2016). "And then came molecular phylogenetics—Reactions to a monographic study of Hypericum (Hypericaceae)". Phytotaxa. 255 (3): 181. doi:10.11646/phytotaxa.255.3.1.