Hymenothrix loomisii, Loomis' Thimblehead
Scientific Name: Hymenothrix loomisii
Common Name: Loomis' Thimblehead
Family: Asteraceae, Sunflower Family
Synonyms: ( )
Duration: Annual, biennial or short lived perennial.
Size: Up to 3 feet.
Growth Form: Forb/herb; erect, 1 or more stems from base.
Leaves: Green; alternate, basal leaves with stalks (petioles), upper leaves sessile; simple pinnately divided, linear lobes, glabrous or with short hairs.
Flower Color: Cream, yellow or bright yellow; flower heads small; disk flowers 10-20, corollas creamy to bright yellow outer florets larger, anthers yellow to light brown; flower heads on short stalks (peduncles), less than 3 inches; fruit an achene.
Flowering Season: June to October, summer and fall after monsoon rainfall.
Elevation: 3,500 to 7,000 feet.
Habitat Preferences: Mesas, plains and disturbed sites especially along roadsides.
Recorded Range: Rare in the United States found only in AZ, CA and NV. Also native to northern Mexico. In Arizona it is found in the central, northern and northwestern parts of the state. Marginally found in California and Nevada.
U.S. Weed Information: No data available.
Invasive/Noxious Weed Information: No data available.
Wetland Indicator: No data available.
Threatened/Endangered Information: No data available.
Comments: Loomis’ Thimblehead is similar in appearance to Trans-Pecos Thimblehead, Hymenothrix wislizeni and to Wright's Thimblehead, Hymenothrix wrightii. Clear visible differences between all three in the flowers, Trans-Pecos Thimblehead is the only species with ray flowers, 5 to 8, Loomis’ and Wright's Thimblehead have only discoid flowers. Wright’s Thimblehead has white or pinkish corollas and pinkish anthers and Loomis’ Thimblehead has cream to yellow corollas and anthers.