Triphora trianthophoros, the threebirds or three birds orchid, or nodding pogonia, is a species of terrestrial orchid native to eastern North America.
Triphora trianthophoros is a small, terrestrial, semi-saprophytic orchid. The showiest member of its genus, T. trianthophoros has 1-8 (often 3, thus the name) nodding flowers that are roughly 2 cm in size and sit atop stems 8âÂÂ25 cm tall. Leaves are small (~1 cm X 1.5 cm) and typically dark green to purple. The orchid blooms from July through September, but is infamous for its elusive nature, with ephemeral flowers lasting for only several hours on a few days of the year. It has further been reported that populations across a region synchronize blooming on specific days, making observation of flowering specimens even more difficult. Several forms of T. trianthophoros exist, including forma albidoflava (Keenan) with white flowers, forma caerulea (P.M. Brown) with blue flowers, and forma rossii (P.M. Brown) with multi-colored flowers.
Triphora trianthophoros is native to the eastern North America, ranging from as far south as Panama and north through Central America and the central and eastern United States into Ontario. Despite its wide distribution, the species is rare throughout much of its range and has been given G3G4 (secured, but with cause for concern) conservation status by NatureServe.
In the Carolinian zone of Southwestern Ontario, T. trianthophoros existed in two populations in the year 1950. It has only been rarely observed in one of them since 2008, Rondeau Provincial Park. It was listed as endangered in 2010 under Canada's Species At Risk Act and Ontario's Endangered Species Act the following year.
Triphora trianthophoros is predominantly found in mixed hardwood forests, however the species also appears in floodplain forests and the margins of bogs or swamps within its range. It is shade-tolerant.
Co-located species often include partridgeberry, maple, and beech trees, and many mycorrhizal associations in the soil microbiome, which are hypothesized to help supplement nutrients under the closed-canopy conditions. T. trianthophoros occurrences are frequently positively correlated with beech spp. occurrences, suggesting a potential plant+fungi+plant interaction of nutrient and photosynthate sharing between the plant species via mycorrhizae.
The central threat contributing to endangerment of Nodding pogonia are invasive species, including other invasive understory plants (Japanese barberry and garlic mustard in Ontario) and invasive earthworms that degrade the organic forest soils.
Any bottlenecking event also threatens this species survival, because they're populations are often small subpopulations or metapopulations. T. trianthophoros commonly reproduce asexually via secondary tuberoids, adding on to the consequences of genetic diversity loss at the hands of a genetic drift event.