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Nine-anther prairie clover - Dalea enneandra
State Rank Reason (see State Rank above)
DRAFT: Requesting feedback on the 2026 revised rank, factors, and State Rank Reason outlined below and in the Conservation Status Rank Report.
Dalea enneadra is rare in Montana, being known from a only few sites in southeast Montana. These occurrences are generally poorly documented in terms of size and extent, as a result, the species' conservation status is imprecisely known though it appears to at least be vulnerable due to its rarity. Threats and population trends are largely unknown.
All occurrences are in need of surveys to better assess population levels and extent, habitat quality and any potential threats to the populations. Several of the recent observations also need to be verified in terms of their identification. Monitoring at least a few sites is needed to be able to determine potential population trends. Additional surveys of potentially suitable habitat within the range of the species are also needed to determine if other occurrences exist in the state.
General Description
Nine-anther Dalea is a perennial herb with 1-3 erect, branched stems, which are 5-10 dm tall and arise from a yellow taproot. The leaves are 13-26 mm long, lack petioles, and are pinnately divided into 2-6 pairs of narrowly elliptic leaflets. Foliage is glandular. The flowers lack stalks and are well separated in spikes at the branch tips. Each white, pea-like flower is 8-11 mm long and is surrounded at the base by a broad, deciduous bract that is 3-4 mm long and has pale margins. The calyx has 5 long, hairy, linear lobes that are 3-5 mm long. The upper petal is 6-7 mm long and only slightly reflexed; there are 9 stamens. The egg-shaped pod is 3-4 mm long and has one seed.
Phenology
Flowering July-September.
Diagnostic Characteristics
The combination of the long, hairy calyx and the 9 stamens separate this plant from other species of Dalea and from species of Psoralea and Amorpha.
Species Range
Montana Range
Range Descriptions
Native
Range Comments
Nine-anther prairie-clover is Great Plains species that is known from North Dakota south to New Mexico and Texas.
Observations in Montana Natural Heritage Program Database
Number of Observations: 15
(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
Gravelly-soiled grasslands and slopes on the plains. Species associated with sites in Montana include Stipa comata, Elymus smithii, Carex filifolia, Calamovilfa longifolia, Cryptantha celosioides, Artemisia tridentata, Artemisia frigida and Yucca glauca.
National Vegetation Classification System Groups Associated with this Species
Shrubland
Sagebrush Shrubland
Grassland
Lowland - Prairie Grassland
Ecology
POLLINATORS The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap:
Bombus auricomus,
Bombus pensylvanicus,
Bombus griseocollis, and
Bombus impatiens (Colla and Dumesh 2010, Williams et al. 2014).
Stewardship Responsibility
Threats or Limiting Factors
STATE THREAT SCORE REASON
Threat impact not assigned because threats are not known (MTNHP Threat Assessment 2021).
References
- Literature Cited AboveLegend:
View Online Publication
Colla, S.R. and S. Dumesh. 2010. The bumble bees of southern Ontario: notes on natural history and distribution. Journal of the Entomological Society of Ontario 141:39-68.- MTNHP Threat Assessment. 2021. State Threat Score Assignment and Assessment of Reported Threats from 2006 to 2021 for State-listed Vascular Plants. Botany Program, Montana Natural Heritage Program, Helena, Montana.
- Williams, P., R. Thorp, L. Richardson, and S. Colla. 2014. Bumble Bees of North America. Princeton, NJ: Princeton University Press. 208 p.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?- Heidel, B. 1990. Inventory of rare plant species in Theodore Roosevelt National Park, Billings and McKenzie counties, North Dakota. Report to the National Park Service. North Dakota Natural Heritage Inventory, Bismarck, North Dakota. 112 pp.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
- North Dakota Natural Heritage Program. 1993. 1991-1992 inventory of rare plant species in the Little Missouri National Grasslands. Unpublished report to the Custer National Forest. Bismarck, North Dakota. 72 pp.
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