''Platanthera ephemerantha'' is a species of

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

known by the common names whiteflower rein orchid, slender white piperia, and white-flowered piperia. It is native to western North America from

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S ...

to the

San Francisco Bay Area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Gov ...

, where it grows in

coniferous forests Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extan ...

and other habitat in coastal and inland mountain ranges within 150 kilometers of the coast. It grows erect to about half a meter in maximum height from a bulbous

caudex A caudex (plural: caudices) of a plant is a Plant stem, stem, but the term is also used to mean a rootstock and particularly a basal stem structure from which new growth arises.pages 456 and 695 In the strict sense of the term, meaning a stem, " ...

. The basal leaves are up to 18 centimeters long by 3 wide. Leaves higher on the stem are much reduced. The upper part of the stem is a spikelike

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed ...

of up to 100 small flowers, mostly arranged along one side of the stem. The fragrant, honey-scented flowers are whiter than those of other ''

Platanthera The genus ''Platanthera'' belongs to the subfamily Orchidoideae of the family Orchidaceae, and comprises about 150 species of orchids. The members of this genus, known as the butterfly orchids or fringed orchids, were previously included in the ...

'', but sometimes green-tinged or -veined, or green with white margins. The status of this species in the wild is difficult to determine because most populations are small and may produce flowers only rarely.California Native Plant Society Rare Plant Profile
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References

External links

Jepson Manual Treatment

USDA Plants Profile

Flora of North America

Photo gallery

ephemerantha ''Dendrobium'' is a genus of mostly Epiphyte, epiphytic and Lithophyte, lithophytic orchids in the Family (biology), family Orchidaceae. It is a very large genus, containing more than 1,800 species that are found in diverse habitats throughout m ...

Orchids of California Orchids of Canada Orchids of the United States Flora of the West Coast of the United States Flora of Alaska Flora of the Klamath Mountains Natural history of the California Coast Ranges Natural history of the San Francisco Bay Area Plants described in 1990 Flora without expected TNC conservation status {{Orchidoideae-stub