BC Conservation Data Centre: Conservation Status Report
Aphyllon corymbosum ssp. mutabile
variable broomrape
| Scientific Name: | Aphyllon corymbosum ssp. mutabile |
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| Scientific Name Synonyms: |
Orobanche corymbosa ssp. mutabilis
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| English Name: | variable broomrape |
| Provincial Status Summary | |
| Status: | S4 |
| Date Status Assigned: | April 30, 2019 |
| Date Last Reviewed: | April 30, 2019 |
| Reasons: | Locally abundant but difficult to quantify, Orobanche corymbosa is scattered throughout BC's southern grasslands in at least 16 occurrences (with many more are expected) over at least 11,000 square km. Livestock use of rangelands is considered a widespread, low-severity threat. |
| Range | |
| Range Extent: | E = 5,000-20,000 square km |
| Range Extent Comments: | Using GIS tools, Orobanche corymbosa is restricted to about 11,000 square km. It appears to be restricted to the Okanagan and Kootenays, but not extending further north into the Kamloops area or into the Cariboo. It may occur over a large area in the Kootenays than is currently documented and thus the total range extent could be greater. |
| Area of Occupancy (km2): | U = Unknown |
| Area of Occupancy Comments: | Unknown. |
| Occurrences & Population | |
| Number of Occurrences: | BC = 6 - 80 |
| Comments: | There are at least 16 occurrences in BC but many more are expected. This subspecies blooms late in the season and is probably overlooked. There is plentiful potential habitat but within a restricted zone within the province. |
| Number of Occurrences with Good Viability / Ecological Integrity: | C = 4 - 12 |
| Comments: |
Most of the occurrences are probably quite viable, as plants are locally abundant and apparently not very threatened, or at least somewhat resilient, in most locations. |
| Number of Occurrences Appropriately Protected & Managed: | BC = 1 - 12 |
| Comments: | One population is effectively protected in an Ecological Reserve. A second population is in a Provincial Park, where the level of protection will depend upon effective communication between management and field staff. |
| Population Size: | BC = 50 - 1,000 individuals |
| Comments: | There are at least 24-220 plants in the BC population but many others expected. They appear to flower somewhat irregularly presumably in response to unstudied weather factors, remaining underground and unseen otherwise (M. Martin, pers. comm. 2007). Numbers, therefore, cannot easily be measured in the absence of a long-term annual study and the documented numbers are probably an underestimate. |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | Widespread, low-severity threat |
| Comments: | This species has likely been impacted by all of the following in some way: residential and recreational development, overgrazing, forest encroachment, road and trail development and off-road recreation use, which have resulted in irreversible losses of native grassland species, throughout southcentral B.C. The primary threat potentially, however, is cattle trampling (though this threat is not considered a severe one as plants appear to be somewhat resilient). |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | U = Unknown |
| Comments: | Unknown, and difficult to assess, but possibly stable. |
| Long-Term Trend: | U = Unknown |
| Other Factors | |
| Intrinsic Vulnerability: | U=Unknown |
| Environmental Specificity: | U=Unknown |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | |
| Inventory Needs: | |
| Stewardship | |
| Protection: | |
| Management: | |
| Version | |
| Author: | Penny, J.L. |
| Date: | October 24, 2007 |
| References | |
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Batten, R. 2018. Vascular plant GeoCAT range extent and index of AOO maps supporting status assessment 2017_18 for British Columbia Conservation Data Centre. March 2018. Victoria, BC. 450 pp.
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British Columbia Conservation Data Centre. Botany Program. 2000. Database containing records of rare plant collections and observations in the province of British Columbia.
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Douglas, G.W. 2004. Excel spreadsheet on 2004 field work done in southern BC by Douglas Ecological Consultants Ltd. (G.W. Douglas, S. Smith, J. Fenneman and H. Janszen).
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Please visit the website Conservation Status Ranks for information on how the CDC determines conservation status ranks. For global conservation status reports and ranks, please visit the NatureServe website http://www.natureserve.org/.
Suggested Citation:
B.C. Conservation Data Centre. 2007. Conservation Status Report: Aphyllon corymbosum ssp. mutabile. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 9, 2026).