Mentzelia conspicua (Chama Blazing Star)

Mentzelia conspicua (Chama Blazing Star)

Photograph by Jim McGrath (2011)
Scientific Name with Author
Mentzelia conspicua Todsen
Common Name
Chama Blazing Star
Rare Plant Conservation Scorecard Summary
Overall Conservation Status Documented Threats Actions Needed

invasive, non-native species

document rarity

County Map
Herbaceous perennial; stems erect, strict, to 60 cm tall, from a basal rosette, pubescent with small, retrorsely barbed hairs and long barbed hairs with the tip acute and the base surrounded by support cells; rosette leaves and stem leaves pinnately lobed, rachis 2-3 mm wide, lobes usually opposite, 6-15 mm long, 2-3 mm wide, lower surface pubescent with stout, curved, pointed hairs, upper leaf surface green, sparsely pubescent with a few scattered pointed hairs; bracts linear or sometimes with a pair of long narrow lobes at base; flowers open in late afternoon; calyx lobes 5, 8-12 mm long, deltoid, acuminate, calyx tube 1.5-2 cm long; petals golden yellow, glabrous, in two whorls of five (inner whorl of 5 petaloid staminodes), ovate to lanceolate, outer whorl 25-45 mm long, 8-11 mm wide, inner whorl 22-34 mm long, 7-10 mm wide, apices acute or notched; fertile stamens numerous, all filaments filiform, outermost filaments 20-27 mm long, innermost 7-10 mm long, anthers 1 mm long; style 24-32 mm long; stigma 1.5 mm long, at anthesis 9-12 mm above the anthers; capsule cylindrical, 15-22 mm long, topped by the persistent calyx lobes; seeds lenticular, dark gray to black when mature, 2-2.8 mm long, wing narrow, to 0.1 mm wide. Flowers late July to early October.
Similar Species
The allopatric Mentzelia laciniata occurs west of the Continental Divide and differs by its smaller flowers, usually alternate leaf lobes, and broad stamen filaments.
New Mexico, Rio Arriba County, upper Rio Chama basin.
Road cuts and barren hillsides, on gray to red shales and clays of the Mancos and Chinle formations in piƱon-juniper woodland; 1,800-2,200 m (5,900-7,200 ft).
A narrow endemic with specific habitat requirements. Its large yellow flowers make it the most beautiful of New Mexico's blazing stars and it is commercially offered for ornamental use. A Torrance County specimen of this species is either mislabeled or represents an introduced occurrence that no longer persists at the site of collection.
Conservation Considerations
Mentzelia conspicua is an early colonizer of disturbed areas (e.g., road cuts) and seems to be crowded out by invasive weeds such as Melilotus. Additional field surveys are needed to determine its abundance in natural areas such as the Chama River Canyon Wilderness.
Important Literature

*Todsen, T.K. 1999. A new endemic species of Mentzelia Sect. Bartonia (Loasaceae) from New Mexico. Sida 18(3):819-822.

Information Compiled By
Tom Todsen 1999

For distribution maps and more information, visit Natural Heritage New Mexico