BC Conservation Data Centre: Species Summary
Zeltnera muehlenbergii
Muhlenberg's centaury
| Scientific Name: | Zeltnera muehlenbergii (Griseb.) G. Mans. | ||||||||||
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| Scientific Name Synonyms: |
Centaurium muehlenbergii
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| English Name: | Muhlenberg's centaury | ||||||||||
| 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: | ZELTMUE | ||||||||||
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| Conservation Status / Legal Designation | |||||||||||
| Global Status: | G5? (Nov 1996) | ||||||||||
| Provincial Status: | S1 (Apr 2019) | ||||||||||
| BC List: | Red | ||||||||||
| Provincial FRPA list: | |||||||||||
| Provincial Wildlife Act: | |||||||||||
| COSEWIC Status: | Endangered (Mar 2008) | ||||||||||
| SARA Schedule: | 1 - Endangered (Feb 2010) | ||||||||||
| General Status Canada: | 1 - At Risk (2010) | ||||||||||
| Ecology & Life History | |||||||||||
| General Description: | |||||||||||
| Technical Description: | |||||||||||
| Subspecies Comments: | No subspecies of Centaurium muhlenbergii are recognized in B.C.; however, the taxonomy of the Centaurium genus is difficult. Further work is required to sort out the systematics of this group. C. muhlenbergii has been misapplied to potentially eight or nine Centaurium species. G. Mansion (a taxonomist specializing in the Centaurium genus) has recommended that a "Centaurium muhlenbergii complex" be recognized which includes C. curvistamineum, C. floribundum, and C. tenuiflorum (G. Mansion, pers. comm., in Miller and Miles 2003). He also suggested that C. muhlenbergii originated from a hybrid between C. erythraea and C. tenuiflorum. | ||||||||||
| Identification Comments: | Centaurium muhlenbergii is a small annual herb that arises from a short taproot. Plants range in height from 3 to 30 cm, but in B.C. they are often 4-5 cm tall. Stems are hairless, and stem leaves are oppositely arranged, narrow, and abruptly-pointed. Basal leaves are few and are wider than stem leaves, egg-shaped, round-tipped, and form a small rosette. The inflorescence consists of a few tube-shaped flowers on stalks that are much shorter than the calyces (tubes formed by fused sepals). Calyces are deeply lobed. Tubes formed by fused petals are white to deep pink and longer than the calyces, and the anthers extend well past the edge of the tube. Fruits are slender capsules with small brown seeds (Douglas et al. 1999; Miller and Miles 2003). | ||||||||||
| Similar Species: | In B.C., there are two other Centaurium species that could be confused with Centaurium muhlenbergii. C. erythraea has a well-developed basal rosette, egg-shaped stem leaves, and flowers that are unstalked or nearly so. C. exaltatum lacks basal leaves, the flower stalks are much longer than the tube formed by the sepals, and the sepals are as long as or longer than the petal tube (Douglas et al. 1999). C. erythraea is an introduced species of roadsides, fields, and waste places, whereas C. exaltatum is found in moist saline meadows in interior B.C. (Douglas et al. 1999). C. muhlenbergii is the only Centaurium species found in vernal meadows and salt marshes in coastal B.C. | ||||||||||
| Provincial Reproduction Comments: | Asexual reproduction does not occur in Centaurium muhlenbergii. Being an annual plant, it depends on sexual reproduction for persistence. Flowers are showy and have nectary glands, which suggests that insect pollination occurs or did occur. Both outcrossing and self-pollination are known to occur in the genus Centaurium, but no specific information exists on the pollination ecology of C. muhlenbergii. Each flower produces a slender capsule that contains several seeds. Successful seed production was observed during field surveys in 2002 (Miller and Miles 2003). The genetic variability in the B.C. populations and their genetic distinctness from populations in Oregon (ca. 500 km away) has not been studied. Because of the great distance between these populations and apparent low dispersability of the species, it has been hypothesized that distinct ecotypes may have evolved due to differences in environmental conditions between regions (Miller and Miles 2003). | ||||||||||
| Provincial Ecology Comments: | Basic ecological information is lacking for Centaurium muhlenbergii. Specific factors affecting population survival, population age structure, recruitment rate, seedling survival rates, mortality rates, and growth rates are not known (Miller and Miles 2003). Year-to-year fluctuations in size and other characteristics of the two populations have also not been studied. C. muhlenbergii does not appear to have any innate mechanism of seed dispersal (Miller and Miles 2003). Poor dispersability seems likely since no new occurrences have been documented in over 40 years (the two C. muhlenbergii populations were first reported in 1933 and 1961) despite an increased search effort in recent years (Miller and Miles 2003). Seeds exhibit primary dormancy, i.e., they are dormant at the time of seed dispersal. Germination requirements and early stages of development are unknown. The number of years that seeds are dormant/viable in the soil before germinating is also not known. This information, as well as a basic understanding of seed bank dynamics of C. muhlenbergii may be critical in determining how resilient the seed bank (population) is to drought and other factors. C. muhlenbergii appears to be a poor competitor. It requires open patches of bare soil for growth and germination, and may be susceptible to competition from invasive grasses (M. Fairbarns, pers. comm., in Miller and Miles 2003). Pests and diseases of C. muhlenbergii have not been observed. | ||||||||||
| Habitats: (Type / Subtype / Dependence) |
Forest / Garry Oak Woodland / Facultative - frequent use
Grassland/Shrub / Garry Oak Maritime Meadow / Facultative - frequent use Grassland/Shrub / Meadow / Facultative - frequent use Other Unique Habitats / Vernal Pools/Seasonal Seeps / Facultative - frequent use |
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| Global Habitat Comments: | Moist, open forest; <500 m. | ||||||||||
| Provincial Habitat Comments: | Centaurium muhlenbergii is currently found in two distinct habitat types in B.C.: a vernal pool within a large meadow in a Garry oak woodland, and along the margins of a tidal saltgrass marsh (Miller and Miles 2003; B.C. CDC Element Occurrence Data 2005). Both habitat types are characterized by a sub-Mediterranean-like climate with dry, warm summers and mild, wet winters, and in which most precipitation falls during the winter months. Both habitat types also experience seasonal flooding by rainwater or by the ocean. Vernal pools and depressions in B.C. typically form on relatively level sites underlain by bedrock or by an impervious hardpan soil layer, and they experience winter and spring inundations followed by complete drying in late spring (Miller 2003). Salt marshes are the upper vegetated portions of intertidal mudflats, often in sheltered locations, which undergo varying frequency of inundation. C. muhlenbergii occurs in a drier part of a saltmarsh, which likely only occasionally experiences tidal inundation. The species occurs in patches of open, bare, moist soil within the habitat types. The habitats of C. muhlenbergii occur within Garry oak ecosystems, which are located in the drier subzone of the Coastal Douglas-fir zone (CDFmm) (Douglas et al. 2002). The Garry oak ecosystem is very restricted in B.C. and has been reduced to less than 5% of its original extent (Fuchs 2001). Associated species at the vernal pool site are Camassia quamash, Holcus lanatus, Agrostis spp., Dactylis glomerata, Poa bulbosa, and Cynosurus cristatus (Miller and Miles 2003). At the saltmarsh site, associated species are Distichlis spicata, Epilobium ciliatum, Cotula coronopifolia, Hypochaeris radicata, and Juncus balticus (Miller and Miles 2003). C. muhlenbergii was also previously recorded in Stanley Park (no collections since 1911), but no information was given regarding habitat type. | ||||||||||
| Provincial Phenology: (1st half of month/ 2nd half of month) |
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| Provincial Phenology Comments: | There is little information about the phenology of Centaurium muhlenbergii. Miller and Miles (2003) reported that the species is an annual herb that flowers between June and August, produces seeds that are dormant all winter, and germinates in spring. The month-by-month phenology (above) is an estimate of C. muhlenbergii's life cycle. | ||||||||||
| Elevation (m) (min / max): | Provincial: 0 / 5 | ||||||||||
| Known Pests: | |||||||||||
| Pollen Vector: | |||||||||||
| Pollinator: | |||||||||||
| Dispersal: | |||||||||||
| Provincial Inventory | |||||||||||
| Inventory Priority: | |||||||||||
| Ownership of occurrences (Known locations): | Mixed government | ||||||||||
| Inventory Need: | C-D. There is a moderate to low priority for new inventories for this species. Miller and Miles (2003) suggest that new populations of Centaurium muhlenbergii could be found on southern Vancouver Island and the Gulf Islands, especially in tidal marshes along the coast where little collecting has been done. There may also be more subpopulations of C. muhlenbergii on Chatham Island. | ||||||||||
| Inventory Comments: | M. Miller did a week-long search of potential Centaurium muhlenbergii habitat on southeast Vancouver Island in July 2002 as a means of locating additional populations. Sixteen different localities were surveyed, but no new populations were located (Miller and Miles 2003). In addition, the Garry Oak Recovery Strategy has recently enabled expert botanists to undertake a concerted inventory of preferred habitats for C. muhlenbergii, such as vernal pools and coastal wetlands in the Garry oak ecosystem. New populations would likely have been documented during these searches if they existed. However, salt marsh habitats may not be as well inventoried as other plant communities in the Garry oak ecosystem complex, and may yield new populations. | ||||||||||
| Economic Attributes | |||||||||||
| Provincial Economic Comments: | There are no known economic uses of Centaurium muhlenbergii in B.C. It was not used by First Nations in B.C., but in California it was used as a laxative by the Mahuna First Nation (MPNADB 1999 in Miller and Miles 2003). C. muhlenbergii is wild-crafted for herbal remedies (mostly poor appetite and digestive problems) in the Pacific Northwest region. Other Centaurium species, and likely C. muhlenbergii, are known for their unique phytochemicals which have a range of uses from yellow dyes to herbal remedies for digestive problems (Miller and Miles 2003). Closely related C. erythraea (a potential parent of C. muhlenbergii) is known for its anti-inflammatory, antipyretic, antioxidant, antimutagenic, and diuretic effects (Berken et al. 1991 in Miller and Miles 2003). . | ||||||||||
| Distribution | |||||||||||
| Endemic: | N | ||||||||||
| Global Range Comment: | CA (Northern CA, Humboldt Co., Cascade Range Foothills, northern Sierra Nevada Foothills, south Sacramento Valley, north San Joaquin Valley, north and central Central Valley, northern Modoc Plateau), to ID, west NV, and north to Oregon and Washington. | ||||||||||
| Disjunct, more common elsewhere: | Y | ||||||||||
| Peripheral, major distribution elsewhere: | Y | ||||||||||
| Authors / Contributors | |||||||||||
| Global Information Author: | |||||||||||
| Last Updated: | |||||||||||
| Provincial Information Author: | Bartemucci, P. | ||||||||||
| Last Updated: | Feb 24, 2005 | ||||||||||
| Last Literature Search: | |||||||||||
| References and Related Literature | |||||||||||
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. |
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Douglas, G.W., D. Meidinger, and J. Pojar. eds. 1999. Illustrated Flora of British Columbia, Vol. 3, Dicotyledons (Diapensiaceae through Onagraceae). B.C. Minist. Environ., Lands and Parks, and B.C. Minist. For., Victoria. 423pp. |
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Miles, W. 2002. Stewardship Account for Muhlenberg's Centaury Centaurium muehlenbergii. Prepared for the B.C. Conservation Data Centre and the Garry Oak Ecosystems Recovery Team. Sponsored by the Habitat Stewardship Program, Gov. Can. and Nat. Conservancy Can. Victoria, BC. 15pp. |
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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. Species Summary: Zeltnera muehlenbergii. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 4, 2026).