Arethusa bulbosa L.
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TAXONOMY
 
Family: Orchidaceae
Genus: Arethusa
 
Species Synonyms: none
Common Names: swamp-pink
dragon’s-mouth
 
DISTRIBUTION
 
Canada: northeastern and east-central Saskatchewan – Manitoba – Ontario – Quebec – Labrador – Newfoundland – Nova Scotia
Saskatchewan: northwestern – east-central Saskatchewan; Lake Athabasca – Nipawin
Ecoregion: Boreal Transition, Mid-Boreal Upland, Mid-Boreal Lowland, Athabasca Plain
 
HABITAT
 
Saskatchewan: open, drying, treed Sphagnum bogs
Canada: Sphagnum bogs and peaty meadows
 
RARITY STATUS
 
Provincial Status According
to Harms (2003):
Endangered
Nature Conservancy Status:
G4 S1
Saskatchewan Species at
Risk Status:
None
COSEWIC Status:
None
 
Arethusa bulbosa is threatened because it is rare or uncommon in Saskatchewan. Most populations are small. No immediate threats are known but are possible in the future.
 
SPECIES DESCRIPTION
 
Stems: scapose; corm small, bulbous
Leaves: solitary, basal, tubular sheaths 2 – 3, blade 4 – 20 cm long, 3 – 12 mm wide, linear-lanceolate, grass-like, obscurely plicate, reduced to sheaths or absent at flowering
Inflorescence: terminal, flowers solitary, rarely 2, peduncle 10 – 40 cm long; floral bracts minute, 2 – 4 mm long, 2 mm wide
Flowers: resupinate, erect, showy; calyx 2 – 4 cm long, 4 – 9 mm wide, oblanceolate, bright magenta to pinkish-white, forming a hood; corolla 2 – 3 cm long, 3 – 8 mm wide, bright magenta to pinkish-white; labellum 2 – 2.5 cm long, 1 – 1.5 cm wide, curved downwards, whitish-pink to white in the centre, may have yellow or be spotted with purple, numerous yellowish hairs in centre, margin wavy; anther with pair of soft yellowish-green pollinia; stigma emergent, with free lateral lobes
Fruits: capsules erect
 
ORCHIDACEAE KEY FOR GENERA FOUND IN SASKATCHEWAN
 
1 Plants saprophytic, without chlorophyll, yellowish to brownish; leaves reduced
Corallorhiza
1 Plants not saprophytic, with chlorophyll, green; leaves well developed
2
   
2 Labellum saccate, not spurred
3
2 Labellum not saccate, may be spurred
5
   
3 Leaves several
Cypripedium
3 Leaves solitary to 2
4
 
4 Leaf oval to round
Calypso
4 Leaf linear
Arethusa
 
5 Basal spur on lip
6
5 Basal spur absent
9
 
6 Leaves cauline
7
6 Leaves basal
8
 
7 Pollinia parallel or nearly so; lip unlobed
Platanthera
7 Pollinia divergent; lip notched to three lobed
Coeloglossum
 
8 Labellum white, spotted with purple, calyx and corolla rose
Amerorchis
8 Flowers greenish or white
Habenaria
 
9 Leaves 2
10
9 Leaves 1 – several
11
 
10 Leaves in basal pair
Liparis
10 Leaves in the middle of the stem
Listera
 
11 Flowers greenish; stems swollen at base to pseudobulb
Malaxis
11 Flowers white, cream, yellow or brown, occasionally tinged with green; pseudobulb absent
12
 
12 Leaves reticulate marked, midrib white; flower spike not twisted; woodlands
Goodyera
12 Leaves not reticulate marked, midrib green; flower spike twisted; prairies
Spiranthes