Species: Tradescantia occidentalis (Britt.) Smyth

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Tradescantia occidentalis (Britt.) Smyth

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TAXONOMY

Family:

Commelinaceae

Genus:

Tradescantia

Species Synonyms:

none

Common Names:

western spiderwort
prairie spiderwort
spiderwort

DISTRIBUTION

Canada:

southeastern Alberta, south-central Saskatchewan, southwestern Manitoba

Saskatchewan:

south-central Saskatchewan; Elbow Sand Hills

Ecoregion:

Moist Mixed Grassland

HABITAT

Saskatchewan:

southwest-facing slopes on semi-active to stabilized sand dunes and sandy prairies

Associated Species:

Achnatherum hymenoides, Elymus lanceolatus ssp. psammophilus, Cyperus schweinitzii, Dalea villosa var. villosa, Hesperostipa comata, Psoralidium lanceolatum

RARITY STATUS

Provincial Status According
to Harms (2003):

Endangered

Nature Conservancy Status:

G5 S1

Saskatchewan Species at
Risk Status:

Endangered

COSEWIC Status:

Threatened

Tradescantia occidentalis is endangered because it is regionally restricted and the Saskatchewan population is isolated from the populations in Manitoba, Alberta, and the United States. Also, this plant thrives in a delicate sand dune environment and may be affected by cattle grazing and other human uses of the land. This species is usually locally numerous within each population, but threats like Euphorbia esula invasion may cause population decline in the future.

SPECIES DESCRIPTION

Height:

30 – 70 cm

Roots:

fibrous roots fleshy

Stems:

herbaceous perennial, erect, branched, persistent leaf bases papery, glaucous, glabrous, mucilaginous; nodes 2 – 6, swollen, internodes to 25 cm long;

Leaves:

alternate, sheath inflated to 2 – 4 times width of blade, blade 9 – 33 cm long, 4 – 12 mm wide, often folded, grass-like, linear, venation parallel, somewhat glaucous, glabrous, mucilaginous

Inflorescence:

cyme scorpioid, terminal at end of main branches and stems, few to many flowered, 1 – 2 flowers open at a time per inflorescence; bracts 2, 6 – 20 cm long, foliaceous, glabrous; pedicels to 20 mm, glandular

Flowers:

calyx 3-merous, 8 – 13 mm, 2 – 3 mm wide, elliptic to lanceolate, green, glandular-pubescent; corolla 3-merous, 8 – 15 mm long, ovate, dark purple to light purple to pink, deliquescent; stamens 6, filaments purple or pink, appendaged, anthers bright yellow; ovary superior, 3-carpellate; stigma and style purple, glandular to glabrous

Fruits:

capsule 3-valved; seeds 2 – 6, 2 – 4 mm long, compressed oblong

*HOW TO IDENTIFY TRADESCANTIA* IN SASKATCHEWAN**

Tradescantia occidentalis is the only member of the Commelinaceae native to Saskatchewan. Although this plant may look grass-like in its vegetative state, it can easily be identified by the purple flowers, mucilage, and inflated leaf sheaths.