Tetraneuris acaulis Greene

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Tetraneuris acaulis is a North American species of flowering plants in the sunflower family. It is known by many common names in English including stemless four-nerve daisy, stemless hymenoxys, butte marigold, and stemless rubberweed.

Description

Tetraneuris acaulis is a highly variable perennial plant that grows from a large, coarse taproot. It may be moderate in size or an extremely short herbaceous plant, 2 centimeters to over 30 centimeters in height when flowering. The plants lack stems with all the clustered leaves growing directly from the base of the plant at ground level (basal leaves). The leaves are tightly packed and may be spoon shaped (spatulate) or like a spear head with the widest part in the end third (oblanceolate), sometimes narrowly so (linear-oblanceolate). The leaf edges lack teeth or divisions and may either be hairy or smooth.

Each flowering stem has a single flower head at the end, though very rarely a stem may have two flower heads on a single stem. The flowering stem does not have any leaves (a scape) and each plant may grow between one and thirty-five flowering stems, but occasionally a plant may produce as many as sixty. They are also are quite variable in the length, ranging from 0.5 to 30 centimetres (0.2 to 10 inches).

The flowering head will have a large number of small disc flowers, ranging from twenty-five to over two-hundred. The ray flowers at the edge of the flowering head usually number from eight to fifteen, but may occasionally number as many as twenty-one. The petals (ligules) are showy, 5–20 mm (1⁄4–3⁄4 in) long and fairly wide, 3–8 mm (1⁄8–5⁄16 in). Both the ray and the disc flowers are predominantly bright yellow in color. Some plants may have no ray florets. It may flower anytime from April to October in its native range, though different varieties have slightly different flowering seasons.

The fruits are dry achenes only a few millimeters long.

Tetraneuris acaulis - Wikipedia

Tetraneuris acaulis var. arizonica

Tetraneuris acaulis var. caespitosa

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