Myosurus minimus (Least Mousetail) - photos and description
Looking straight down on plant in above photo.
Plants with 5 sepals and 0 to 5 petals.
Leaf in above photo.
General: Tiny annual with a tuft of narrow, linear leaves. Plants glabrous, acaulescent.
Flowers: Flowers grow in terminal, solitary spikes, we measured spikes to 22 mm long. Flowers with 5 elliptical, greenish-white sepals, 0 to 5 linear, yellowish-green petals, and up to 10 stamens. We measured sepals at 3 mm long by 1 mm wide, and petals at 2 mm long by 0.5 mm wide.
Leaves: Leaves are all basal, we measured a leaf at 20 mm long by 1 mm wide.
Height: Height not given in Budd's Flora or Flora of Alberta. We measured plants to 35 mm tall.
Habitat: Prairie mud flats and moist depressions.
Abundance: Very rare, ranked as an S3 (as of 2021) by the Saskatchewan Conservation Data Centre.
Origin: Native.
Similar species: We have two Myosurus species native to Saskatchewan, I believe this plant is Myosurus minimus (and not the other species M. apetalus). Most of the taxonomic keys I have read to distinguish between these two species require observing the beak of the achenes. Achenes were not present, these plants were still flowering.
The Flora of Canada however, has a key for Myosurus
that separates the two species on several other characteristics that I was
able to observe with the plants I photographed:
- M. minimus with sepals to 3(4) mm long, M. apetalus with
sepals to 2.5 mm long.
- M. minimus with stamens 5 to 10, M. apetalus with
stamens usually 5.
- M. minimus with spike to 5 cm long, M. apetalus
with spike usually not over 1 cm long.
- M. minimus with sepals lightly 3(5)-nerved, M. apetalus
with sepals 1-nerved (rarely with a pair of faint lateral
nerves). I did not observe any nerves on the sepals on the plants I
found.
When and where photographed: Photos taken May 30th, during a steady rainfall, on a moist depression in prairie, Cypress Hills, about 450 km south west of our home in Regina, SK.