Bractless blazingstar - Mentzelia nuda
State Rank Reason (see State Rank above)
Rare and peripheral in Montana, where it is known from a few locations in the eastern half of the state. Additional data on population levels and trends are needed.
Bractless Mentzelia is an herbaceous biennial or short-lived perennial with one to a few erect, branched stems that arise from a taproot and are up to 1 m high. The lance-shaped, alternate leaves are 4-10 cm long, have deeply-toothed margins, and are petiolate below but sessile above. Foliage is covered with short, barbed hairs that cause it to stick to clothing like velcro. Flowers that open in late afternoon are borne on short stalks arising from the axils of reduced upper leaves, or bracts. Each flower is 4-9 cm across and has 10, non-overlapping, white petals and numerous exserted stamens. The calyx forms a deep bowl with 5 narrow, pointed lobes that are 10-25 mm long; it also contains the ovary and bears the stamens. The cylindrical seed capsules are 2-3 cm long.
Flowering in July.
Mentzelia decapetala has ten white petals, its larger flowers are 8-15 cm across, and its petals overlap.
E. MT and SD south to CO, KS, and TX. Peripheral.
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
Sandy or gravelly soil of open hills and roadsides on the plains.
- Additional ReferencesLegend: View Online Publication
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- Brown, D. K. and R. B. Kaul. 1981. Floral structure and mechanism in Loasacae. American Jounal of Botany 68(3):361-372.
- Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.