Carex saximontana
Author: Mackenzie

Rocky Mountain sedge

Cyperaceae (Sedge Family)

Close up of Carex saximontana by Pamela Smith.
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Close up of Carex saximontana by Pamela Smith.
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Taxonomic Comments

Synonyms inlcude: Carex backii Boott var. saximontana (Mackenzie) B. Boivin; C. backii var. subrostrata (Bates) Dorn; C. durifolia L. H. Bailey var. subrostrata Bates

Ranks and Status

Global rank: G5
State rank: S1
Federal protection status: None
State protection status: None

[+] Description and Phenology

No artwork available.

General description: Culms 2.5–35 cm tall, caespitose. Leaves flat, 2-5 mm wide; basal sheaths pale to medium brown; blades dark green to greenish glaucous, longer than stems, leathery, with margins white-hyaline, smooth or scabrous. Bracts leaf-like, longer than the inflorescence. Lateral spikes 0–2, basal, on erect peduncles. Terminal spikes with staminate portion 2–3-flowered; pistillate portion 2–6-flowered (Ackerfield says: spikes solitary, androgynous, few-flowered). Pistillate scales green, leaf-like and essentially concealing perigynia, apex acute; distal scales lanceolate to ovate, apex awned to acute. Staminate scales green or white, ovate to oblong, margins connate near base or for entire length, enfolding scales above, white or with brown subapical band, apex obtuse. Anthers 1–1.5 mm. Perigynia 4-5 mm long, pale green, obovoid, tightly enveloping achenes, apex abruptly tapered, papillose on distal 1/3; beak 0.6–1.2 mm, scabrous. Stigmas 3, club-shaped, erect, short, thick, minutely papillose. Achenes pale to dark brown, 2.5–3 × 1.6–2.4 mm (Flora of North America 2002, Ackerfield 2015).  Please see photographs of perigynium in Ackerfield (2015).

Look Alikes: Carex backii has longer perigynia, 5-6 mm long, with the upper third of the body empty, beaks stout, 2-3 mm long, and smooth margined. Carex saximontana perigynia are 4-5 mm long, the upper part of the body filled by the achene, beaks 0.5-1 mm long, with more or less serrulate margins (Weber and Wittmann 2012).

Phenology: Information on collections from Colorado indicates that this species flowers in May and produces fruits in June and early July.

[+] Herbarium Photos

Images of Carex saximontana housed at the Colorado State University Herbarium.

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[+] Habitat

Habitat of Carex saximontana by Pamela Smith.
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Habitat of Carex saximontana by Pamela Smith.
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In Colorado, Carex saximontana is found in dry to mesic, sandy to rocky soils in mixed conifer forests, thickets, woodlands, and canyons (Weber and Wittmann 2012, Ackerfield 2015, Colorado Natural Heritage Program Occurrence Records 2017). Associated species include: Pseudotsuga menziesii, Pinus ponderosa, Populous tremmuloides, Jamesia americana, Ribes cereum, Quercus gambellii, Mahonia repens, Galium boreale, Carex pennsylvanica, Leucopoa kingii, Muhlenbergia montana, Koeleria macrantha. Helianthus pumilus, Carex geophila, Carex rossii, Leymus ambiguous, Ceanothus fendleri, Carex geyeri, Carex rosii, Smilax lasionerura, Viola rydbergii, Galium aparine, Toxicodendron radicans, Rhus trilobata, Smilacena stellata, Delphinium geyeriCarex inops ssp. heliophila, Prunus virginiana, Rhus trilobata, Amelanchier utahensis, Penstemon vierns, Allium cernuum, Artemisia ludoviciana, Delphinium nuttallianum, Drymocallis fissa, Heuchera parviflora, Hesperostipa comata, Hesperostipa nelsonii, Elymus elymoides, Carex pennsylvanica (Colorado Natural Heritage Program Occurrence Records 2017).

Elevation Range: 5,394 - 8,441 feet (1,644 - 2,573 meters)

[+] Distribution

Distribution of Carex saximontana in Colorado according to mapped land ownership/management boundaries (CNHP 2017, COMaP).
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Distribution of Carex saximontana in Colorado.
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Colorado endemic: No
Global range: Known from Alberta to Ontario south to Colorado and Iowa (Flora of North America Editorial Committee 2002; NatureServe Network Database as of February 2017).  Also reported further west, to Nevada and Washington (USDA NRCS 2017).
State range: In Colorado, found in Boulder, Douglas, Jeferson, and Larimer counties in Colorado (SEINet 2017).

[+] Threats and Management Issues

In Colorado, the primary concerns appear to be incompatible grazing, recreational use, and competition from non-native plants (Colorado Natural Heritage Program Occurrence Records 2017).  Colorado climate scenarios for 2050 suggest temperature will increase by 3-7 F and precipitation may decrease or increase. The impact to any given rare plant habitat is likely to vary. Long-term monitoring that includes weather and soil moisture data is critical to understanding climate impacts.

[+] References

    • Ackerfield, J. 2015. Flora of Colorado. Brit Press, Botanical Research Institute of Texas, Fort Worth, TX. 818 pp.
    • Colorado Natural Heritage Program and the Geospatial Centroid. 2017. The Colorado Ownership and Protection Map (COMaP). Colorado State University, Ft. Collins, CO.
    • Cronquist, A., A. H. Holmgren, N. H. Holmgren, J. L. Reveal and P. K. Holmgren. 1977. Intermountain Flora Vascular Plants of the Intermountain West, USA: vol. 6. New York Botanical Garden, Bronx, NY.
    • Flora of North America Editorial Committee. 2002. Flora of North America north of Mexico. Vol. 23. Magnoliophyta: Commelinidae (in part): Cyperaceae. Oxford Univ. Press, New York. xxiv + 608 pp.
    • Harrington, H. D. 1954. Manual of the Plants of Colorado. Sage Books, Denver, CO. 666 pp.
    • Hermann, F. J. 1970. Manual of the Carices of the Rocky Mountains and Colorado Basin. U.S.D.A. Forest Service Agriculture Handbook No. 374.
    • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
    • Southwest Environmental Information Network (SEINet). 2017. Collections Databases. Online. Available: Acessed 2017.
    • USDA, Natural Resources Conservation Service, PLANTS Database [USDA PLANTS]. Accessed 2017.
    • Weber, W. A. and R. C. Wittmann. 2012. Colorado Flora, Eastern Slope, A Field Guide to the Vascular Plants, Fourth Edition. Boulder, Colorado. 555 pp.
    • Weber, W. A. and R. C. Wittmann. 2012. Colorado Flora, Western Slope, A Field Guide to the Vascular Plants, Fourth Edition. Boulder, Colorado. 532 pp.
    • Welsh, S.L., N.D. Atwood, S. Goodrich, and L.C. Higgins (eds.) 1993. A Utah flora. 2nd edition. Brigham Young Univ., Provo, Utah. 986 pp.

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