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Montana Field Guide

Montana Field Guides

Tiny Swamp Saxifrage - Micranthes apetala
Other Names:  Saxifraga integrifolia Hook. var. apetala, Saxifraga apetala

Species of Concern

Global Rank: G3Q
State Rank: S2?
* (see State Rank Reason below)

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank: 3
C-value:

External Links






State Rank Reason (see State Rank above)
Known from two occurrences, one in the East Pioneers and one in the Absaroka-Beartooth Wilderness. Both occurrences are known from single specimen collections. Though little data are available for the species in Montana, the alpine habitat in which it grows is not generally subject to negative impacts from human disturbance.
 
General Description
Tiny Swamp Saxifrage is a short-lived perennial herb with erect, leafless stems that are 5-10 cm high and arising from a short, often bulblet-bearing rhizome. Rosette leaves are 13-35 mm long and are egg-shaped with a short, broad petiole. The leaves have scattered, long, white or brown hairs, while the stem is densely covered with white, gland-tipped hairs. 5-15 short-stalked flowers are borne in a congested, terminal, egg-shaped cluster. Each saucer-shaped flower has 5 separate, ascending, green sepals that are 1-3 mm long and 10 white stamens attached to the middle of the ovary. The top half of the ovary forms a lobed disk with usually 2 short styles.

Phenology
Flowering in mid-June-July.

Diagnostic Characteristics
Saxifraga has many similar-appearing species; a technical key and hand lens are necessary for identification. Saxifraga oregana var. subapetala also lacks petals, but the stamens are purple. Saxifraga integrifolia is also very similar, but it has petals and the inflorescence is less congested. Saxifraga rhomboidea is the most common high-elevation species, but it also has petals.

Species Range
Present
 


Range Comments
Range about 10,000+ sq. mi. Occurs along the eastern slope of Washington Cascades (Okanogan to Yakima Counties) and disjunct in Montana.

Summary of Observations Submitted for Montana
Number of Observations: 25

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat
Moist, open, often gravelly soil in meadows and on rock ledges in the montane to alpine zones.

Ecological Systems Associated with this Species

References
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Citation for data on this website:
Tiny Swamp Saxifrage — Micranthes apetala.  Montana Field Guide.  .  Retrieved on , from