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Nine-anther prairie clover - Dalea enneandra
State Rank Reason (see State Rank above)
Dalea enneadra is rare in Montana where it is known from a few sites in the southeastern portion of the state. Population count and extent data is poorly documented, and trends are unknown. The identification of many observations made since 2017 need verification. Potential threats are largely unknown. As a result, the species' conservation status rank is imprecisely known, though its rarity makes it at least vulnerable to extirpation in the state.
Revisits to known occurrences, at specified intervals, is greatly needed to collect data on population parameters, habitat conditions, and potential threats - and to assign an accurate and timely species' conservation status rank. Monitoring at a subset of occurrences is necessary to track population trends. Additional surveys into areas of potentially suitable habitat is also needed.
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: 18
(Click on the following maps and charts to see full sized version)
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
Reported threats to Montana's populations of Nine-anther Prairie Clover have not been identified.
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.
- Web Search Engines for Articles on "Nine-anther prairie clover"
