Platanthera unalascensis (Spreng.) Kurtz

Alaska Orchid, Slender Spire Orchid

Habit: Platanthera unalascensis. ~ By Lorne Heshka. ~ Copyright © 2024. ~

Leaves: Platanthera unalascensis. ~ By Herman H. Giethoorn. ~ Copyright © 2024. ~

Flowers: Platanthera unalascensis. ~ By Anthony Valois. ~ Copyright © 2024. ~ ~ National Park Service, Santa Monica M

Inflorescences: Platanthera unalascensis. ~ By Hal Horwitz. ~ Copyright © 2024. ~

Fruits: Platanthera unalascensis. ~ By Anthony Valois. ~ Copyright © 2024. ~ ~ National Park Service, Santa Monica M

Plant form: Platanthera unalascensis. ~ By Lorne Heshka. ~ Copyright © 2024. ~

Facts About

Accepted Synonyms: Habenaria unalaschensis, Piperia unalascensis, Platanthera foetida, Spiranthes unalascensis

Platanthera unalascensis, commonly known as the Alaska Orchid is found from the Aleutians south to Baja California with disjunct populations in the Great Plains, Great Lakes area, and eastern Canada. This orchid grows up to 70 cm, usually with more than 6 stem bracts and basal leaves that wither before flowering. The slender spike has up to 100 loosely spaced, small yellowish green flowers. The petals are erect and sickle-shaped. The labellum is blunt with a fleshy central thickening. The nectar spur is stout and about as long as the labellum. It grows in various habitats including open mixed and coniferous forests, roadsides, tundra, outcrops, floodplains, thickets, and meadows. Plants in coastal populations may be shorter and more densely flowered. This orchid has a disagreeable ammonia-like smell.

Platanthera unalascensis is considered globally secure.

Pollination

This orchid is pollinated by moths in the genera Eupithecia, Oidaematophorus and Platyptila with pollinaria attached to the proboscis.

Notes on Subspecies and Varieties

Ecosystem Type

Cliffs balds or ledges, floodplains, forests, meadows, shrublands or thickets, tundra

Characteristics

Habitat:: terrestrial

Leaf arrangement:: basal

Number of leaves on stem:: absent

Form of the labellum:: the labellum is not pouch-like

Labellum outline:: the labellum is simple

Main color of labellum:: green to brown

Nectar spur:: present

Inflorescence type:: the inflorescence is a spike

Labellum characteristics:

the labellum has a spur
the labellum is simple

Labellum length:: 2–5 mm

Sepal length:: 2–4 mm

Plant height:: Up to 75 cm

Show All Characteristics

Flowers
Floral bract length:

3–23 mm

Flower petal color:

green

Flower symmetry:

the flower is zygomorphic
Flowering date:
April

May

June

July

August
Flowers per inflorescence:

Up to 100

Form of the labellum:

the labellum is not pouch-like

Hairs on inflorescence axis:

the inflorescence stem is hairless

Inflorescence length:

3–44 mm

Inflorescence type:

the inflorescence is a spike
Labellum characteristics:
the labellum has a spur

the labellum is simple
Labellum length:

2–5 mm

Labellum outline:

the labellum is simple

Labellum position:

the flowers are resupinate

Lower petal strongly red-veined:

no

Main color of labellum:

green to brown

Nectar spur:

present

Nectar spur length:

2–5.5 mm

Number of stamens:

1

Orientation of side petals:

the lateral petals are erect

Self-pollinating flowers:

there are no cleistogamous flowers

Sepal length:

2–4 mm

Sepals fused only to sepals:

the sepals are fused to each other (not other flower parts), at least near their bases

Shape of viscidium:

oval

Spots on labellum:

no
Fruits or seeds

Fruit length:

3.5–10.5 mm

Seed capsule orientation:

the capsule points upwards or outwards
Growth form

Plant height:

Up to 75 cm

Roots:

the rhizomes are non-coralloid

Underground organs:

the plant has one or more swollen storage organs underground, such as bulbs, tubers or corms

myco-heterotrophic or not:

the plant is chlorophyllous
Leaves
Bract relative length:

the bract is longer than the associated flower

Leaf arrangement:

basal

Leaf blade edges:

the leaf edges are entire

Leaf blade length:

38–160 mm

Leaf blade length to width ratio:

2.9–4.6

Leaf blade shape:

oblanceolate
Leaf blade tip:
the tip of the leaf blade is acute

the tip of the leaf blade is obtuse
Leaf blade width:

13–35 mm

Leaves during flowering:

leaves are absent during flowering

Number of bracts on stem:

1–8

Number of leaves on stem:

absent
Place
Ecosystem type:
cliffs balds or ledges

floodplains

forests

meadows

shrublands or thickets

tundra
Habitat:

terrestrial
Location:
Alaska

Alberta

British Columbia

California

Colorado

Idaho

Michigan

Montana

Nevada

New Mexico

Newfoundland and Labrador

Ontario

Oregon

Prince Edward Island

Quebec

South Dakota

Utah

Washington

Wyoming
Facts and Uses

Mycorrhiza

Monitoring

Propagation

Restoration

Native to North America

Yes

North American Conservation Status & Distribution

Conservation Status

	Conservation and Wetland Status
Global Rank	Secure
US Status	N/A
Canadian Status	Secure

	Conservation status for: Alberta
Global Rank	Secure
US Status	N/A
Alberta Rank	Watch List
Alberta Status	N/A
Canadian Status	Secure
Wetland Status	N/A

	Conservation status for: Alaska
Global Rank	Secure
US Status	N/A
Alaska Rank	State Rare
Alaska Status	N/A
Canadian Status	Secure
Wetland Status	Facultative

	Conservation status for: British Columbia
Global Rank	Secure
US Status	N/A
British Columbia Rank	Secure
British Columbia Status	N/A
Canadian Status	Secure
Wetland Status	N/A

	Conservation status for: Colorado
Global Rank	Secure
US Status	N/A
Colorado Rank	N/A
Colorado Status	N/A
Canadian Status	Secure
Wetland Status	Facultative Upland

	Conservation status for: Newfoundland and Labrador
Global Rank	Secure
US Status	N/A
Newfoundland and Labrador Rank	State Rare
Newfoundland and Labrador Status	N/A
Canadian Status	Secure
Wetland Status	N/A

	Conservation status for: Ontario
Global Rank	Secure
US Status	N/A
Ontario Rank	Secure
Ontario Status	N/A
Canadian Status	Secure
Wetland Status	N/A

	Conservation status for: Quebec
Global Rank	Secure
US Status	N/A
Quebec Rank	State Rare
Quebec Status	N/A
Canadian Status	Secure
Wetland Status	N/A

	Conservation status for: Wyoming
Global Rank	Secure
US Status	N/A
Wyoming Rank	Watch List
Wyoming Status	N/A
Canadian Status	Secure
Wetland Status	Facultative Upland

North America Distribution

Adapted from USDA data

Facts About

Pollination

Notes on Subspecies and Varieties

Ecosystem Type

Characteristics

Flowers

Fruits or seeds

Growth form

Leaves

Place

Facts and Uses

Native to North America

North American Conservation Status & Distribution

Conservation Status

North America Distribution