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BC Conservation Data Centre: Species Summary


Carex tumulicola
foothill sedge

 
Scientific Name: Carex tumulicola Mackenzie
English Name: foothill sedge
 
Classification / Taxonomy
Scientific Name - Concept Reference: 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.
Classification Level: Species
Species Group: Vascular Plant
Species Code: CARETUM
Kingdom Phylum Class Order Family
Plantae Anthophyta Monocotyledoneae Cyperales Cyperaceae
   
Conservation Status / Legal Designation
Global Status: G4 (Aug 2023)
Provincial Status: S3S4 (Apr 2019)
BC List: Yellow
Provincial FRPA list:   
Provincial Wildlife Act:
COSEWIC Status: Special Concern (Dec 2022)
SARA Schedule: 1  -  Endangered (Feb 2010)
General Status Canada: 1 - At Risk (2010)
   
Ecology & Life History
General Description:
Technical Description:
Subspecies Comments: None.
Identification Comments: Carex tumulicola is a perennial sedge that arises from short rhizomes. It has a tufted growth habit with stems reaching to about 80 cm. The stems are taller than the leaves. The leaves are flat and arise in circular clusters of 2-3 per stem. Each stem features 3-10 spikes. The few-flowered oblong or cylindrical spikes are bisexual with male flowers occurring above the female flowers. The heads have large awn-like bracts. The lower bracts are mostly longer than the inflorescence. Perigynia are pale green to pale brown. The perigynia are 3.3-5 mm long and are egg shaped or elliptical. Scales are as long as the perigynia, short awned, and have a greenish mid-vein and translucent margins. The fruits are smooth, lens-shaped achenes, 1.8-2.2 mm long (Douglas and Ceska 2001; Ball 2002). Distinctive characteristics are the loosely tufted habit and the large bract surpassing the lower spike.
Similar Species: Carex hoodii has spikes that are more tightly clustered and which lack a large bract that surpasses the lower spikes. Similarly, Carex vallicola does not have large subtending bracts that are longer than the lower flower spikes. In addition, C. vallicola does not exceed 40 cm in height and has pale scales, usually shorter than the perigynia (Miller et al. 2005). Carex tumulicola and C. vallicola, however, do not co-occur in B.C.
Global Reproduction Comments: Fruiting in late spring to early summer (Flora of North America Editorial Committee 2002).
Provincial Reproduction Comments: Carex tumulicola reproduces from achenes and from underground rhizomes. Achenes mature during the summer. Dispersal is by gravity, and possibly by wildlife. It is not known how long the seeds persist in the soil seed bank, but achenes of some Carex species remain viable in the soil for a number years (Miller et al. 2005). The ability of this species to spread by seed and the conditions for successful germination are unknown. Some seed trials in the U.S. have been unsuccessful, but other studies report that this species can reseed successfully once established (Miller et al. 2005). It is certain that C. tumulicola does establish readily from rhizomes or, if disturbed, from rhizome fragments (Miller et al. 2005). The ability of this species to reproduce readily from rhizomes is an advantage to surviving and spreading on sites that are prone to frequent fires. Fire used to be common in the Garry oak woodlands ecosystem complex. Because of the fragmented, isolated nature of the C. tumulicola population, genetic interchange via wind borne cross pollination, seed exchange, or rhizome fragments between different populations is probably very infrequent in B.C.
Provincial Ecology Comments: Carex tumulicola is found in the Coastal Douglas-fir biogeoclimatic zone on Vancouver Island. This zone features a Mediterranean-like climate with warm, dry summers and mild, wet winters. Vernal moisture and summer drought are an important climatic feature. Carex tumulicola is found primarily within the Garry oak woodland ecosystem site series or within associated non-forest ecosystems. Because the species is at the northern edge of its range, it may be more limited in the range of ecosystems in which it can survive. Over most of its range - i.e., western Washington, Oregon and California - it is well known as a hardy adaptable plant (Miller et al. 2005). In B.C., C. tumulicola often occurs along shrubby wetland edges that are dry in summer and wet in winter (Miller et al. 2005). It is possible that this sedge specializes in colonizing sites that are too wet in winter for shrubs and too dry in summer for wetland plants. Miller et al. (2005) state that in the United States, C. tumulicola is known for its versatility in surviving an array of environmental disturbances and extremes. This includes summer drought, winter flooding, mowing, and foot traffic. Its ability to reproduce by underground rhizomes may be an asset in that it allows the species to persist and spread under a grazing or frequent fire regime. Prior to European settlement, frequent fires would have been normal in Garry oak woodlands and associated dry non-forest ecosystems. Similar to a large number of grasses and sedges, B.C. populations of C. tumulicola seem to prefer fairly open, relatively unshaded habitats. Exclusion of fire in the last century has resulted in encroachment of introduced and native shrubs on moist meadows. This could be greatly reducing the preferred habitat of C. tumulicola.
Habitats:
(Type / Subtype / Dependence) 		Forest / Garry Oak Woodland / Facultative - frequent use
Grassland/Shrub / Grassland / Facultative - frequent use
Grassland/Shrub / Meadow / Facultative - occasional use
Wetland / Bog / Facultative - occasional use
Wetland / Fen / Facultative - occasional use
Wetland / Marsh / Facultative - occasional use
Wetland / Swamp / Facultative - occasional use
Global Habitat Comments: This species occurs in forest openings, grasslands, and riparian areas at elevations ranging from 30 to 1200 meters (CCH2 Portal 2023, Flora of North America Editorial Committee 2002).
Provincial Habitat Comments: In Canada, Carex tumulicola is found only on the southeast corner of Vancouver Island and an adjacent offshore island. Within this area, it is found mainly on dry, open areas including dry grassy meadows, forest openings, and non-forested wetland margins (Miller et al. 2005). It is found most often within the Garry oak woodland ecosystem and in ecosystems associated with the Garry oak woodland ecosystem. Soils are variable but usually deep. The species is uncommon on shallow, rocky, overly dry soils. It sometimes occurs on sites that are both seasonally wet and seasonably dry. Occurrences tend to be concentrated on edges of shrub patches. The grass and forb dominated ecosystems where this plant is found have undergone substantial disturbance and modification over the past century. Documented occurrences of C. tumulicola have all been from disturbed weedy sites. Common weedy introduced grasses found associated with C. tumulicola include Agrostis gigantea, Anthoxanthum odoratum, Bromus hordeaceus, Cynosurus cristatus, Dactylis glomerata, Festuca rubra, Holcus lanatus, Poa pratensis, and Vulpia bromoides. Native graminoid associates include Elymus glaucus and Juncus effusus. Common native forbs include Delphinium menziezii, Epilobium densiflorum, Geranium bicknellii, Lupinus polyphyllus, Potentilla glandulosa, Potentilla gracilis, and Vicia sativa. It is probable that aggressive weedy herbs and grasses have been displacing C. tumulicola. Habitat has probably been lost to aggressive introduced and native shrubs including Cystisus scoparius, Symphoricarpos albus, Amelanchier alnifolia, Crataegus species, Rosa nutkana, and Rubus discolor.
Provincial Phenology:
(1st half of month/
2nd half of month)		 May: Flowering, Vegetative / Flowering, Vegetative
Jun: Flowering, Fruiting / Flowering, Fruiting
Jul: Fruiting / Fruiting
Provincial Phenology Comments: The phenology of Carex tumulicola in B.C. is not well known. Flowering occurs in May or June. Seed is set during the summer and is dispersed in late summer or fall. Germination time is not known but probably occurs in the spring following the winter rains. Germination requirements are unknown but may depend on special conditions (Miller et al. 2005).
Elevation (m) (min / max): Provincial:  6 / 60
Known Pests:
Pollen Vector:
Pollinator:
Dispersal:
   
 
Provincial Inventory
Inventory Priority: C - Moderate
Ownership of occurrences (Known locations): Mostly local government
Inventory Need: More search effort for Carex tumulicola is required. Preliminary studies have provided a rough idea of the habitat types and locations where this sedge can be found. It is a rather obscure plant and is not easily differentiated from other more common sedges. Up to 2003, this plant had been identified during the course of general searches for other rare and endangered plant species. To help remedy this situation, more targeted surveys were carried out in 2003 and 2004 (Miller et al. 2005). These surveys successfully recorded several new populations, but not all possible locations were surveyed: two additional populations were discovered in 2005 and 2006 (A. Ceska, pers. comm. 2005; M. Fairbarns, pers. comm. 2006). Prospective sites should be visited during late summer when development of flower heads ensures more accurate identification (Miller et al. 2005). Additional targeted, intensive surveys, could lead to the identification of new populations.
Inventory Comments: Since the late 1990s, approximately 70 subpopulations of Carex tumulicola have been reported, distributed among ten different locations (M. Miller, pers. comm. 2008). The species was first collected and identified in B.C. by T.C. Brayshaw in 1990, but its rarity was not recognized so it was not reported. Later, in 1999, a specimen was collected at Rithet's Bog. This specimen was subsequently confirmed as a rare species by Adolph Ceska (Miller et al 2005). The most substantive and targeted survey for this sedge was done by Mike Miller in 2003 and 2004 (Miller et al. 2005).
 
Economic Attributes
Provincial Economic Comments: There are no documented economic attributes for Carex tumulicola in British Columbia.
 
Distribution
Endemic: N
Global Range Comment: Foot-hill Sedge (Carex tumulicola) occurs in western North America, from southwestern British Columbia, Canada, western Washington, and western Oregon to southern California. Range extent was estimated to be 400,000 square kilometers using herbarium specimens and photo-based observations documented between 1992 and 2023 (CCH2 Portal 2023, Flora of North America Editorial Committee 2002, GBIF 2023, iNaturalist 2023).
Disjunct, more common elsewhere: N
Peripheral, major distribution elsewhere: Y
 
Authors / Contributors
Global Information Author: Nordman, C. (2023).
Last Updated: Aug 21, 2023
Provincial Information Author: K. Simonar, J.L. Penny and S. Hartwell
Last Updated: Feb 21, 2008
Last Literature Search:
   
References and Related Literature
Ball, P. 2002. Carex section Phaestoglochin. Pp. 285-298 In Flora of North America Committee, eds. Flora of North America. Vol 23: Magnoliophyta: Commelinidae (in part): Cyperaceae. Oxford University Press, New York. 606pp.
CCH2 Portal. 2023. Consortium of California Herbaria. Online. Available: https//:www.cch2.org/portal/index.php (accessed 2023).
COSEWIC. 2008k. COSEWIC assessment and status report on the foothill sedge Carex tumulicola in Canada. Comm. on the Status of Endangered Wildl. in Can. Ottawa. vi + 37 pp. Available online .
Douglas, G.W., and Ceska, A. 2001. Carex. Pp.18-158 in G.W. Douglas, D. Meidinger, and J. Pojar, eds. Illustrated Flora of British Columbia, Vol. 6: Monocotyledons, (Acoraceae through Najadaceae). B.C. Minist. Environ., Lands and Parks, and Minist. For., Victoria, BC.
Douglas, G.W., D. Meidinger, and J. Penny. 2002. Rare Native Vascular Plants of British Columbia, 2nd ed. B.C. Conserv. Data Centre, Terrestrial Inf. Branch, Victoria. 358pp.
Douglas, G.W., D. Meidinger, and J. Pojar, eds. 2001. Illustrated Flora of British Columbia, Vol. 6, Monocotyledons (Acoraceae through Najadaceae). B.C. Minist. Environ., Lands and Parks, and B.C. Minist. For., Victoria, BC. 361pp.
Flora of North America Editorial Committee (FNA). 2002b. Flora of North America north of Mexico. Vol. 23. Magnoliophyta: Commelinidae (in part): Cyperaceae. Oxford Univ. Press, New York. xxiv + 608 pp.
Lea, E. 2002. Historical Garry Oak ecosystems of Greater Victoria and the Saanich Peninsula. 1:20,000 scale maps. Prepared for Garry Oak Ecosystems Recovery Team by Terrestrial Inf. Branch, B.C. Minist. Sustainable Resour. Manage., Victoria.
Thuring, C. 2007. Green roofs are growing up. Menziesia 12(2): 1-8.
 

Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.

Suggested Citation:

B.C. Conservation Data Centre. 2023. Species Summary: Carex tumulicola. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 22, 2026).