Trans-Pecos Thimblehead

Hymenothrix wislizeni

Trans-Pecos thimblehead blooming at Academy Village

About the Plant

Trans-Pecos thimblehead is a tall, summer-blooming plant with bright yellow flowers. The divided leaves appear in late spring, the flowers during the summer monsoon rains. It is often found in sandy washes and along roadsides.

Thimblehead is listed in most references as an annual. Personal experience suggest this plant behaves more as a short-lived perennial if grown in a choice site (for example, near irrigation). A bit tall and floppy for a managed landscape, it spreads easily in a naturalized planting.

Wildlife value: Flowers attract butterflies and other insects. Seeds are favored by lesser goldfinch and other seed-eating birds.

More Information

Weekly Plant on Trans-Pecos thimblehead

Map of distribution in US

Technical botanical description from SEINet

 

ID Characteristics

This plant is in the Asteraceae - the aster family.
Trans-Pecos thimblehead grows initially as a rosette of highly divided leaves. For the perennials, this is the overwintering form.
Trans-Pecos thimblehead stays short until the monsoon rains, then it quickly grows to about 3 feet. Most of the leaves are found low on the plant. There are usually several stems, dividing near the top as flowering begins, then producing side shoots from lower leaf axils.
The leaves are alternate and divided into several sections, that each then divide once more. Each division is thin and narrow. The over all dimensions of the leaf are 3-4 inches long x 2-3 inches wide.
The flowers are held in terminal clusters. Each flower head is made of a few ray flowers, each with a 3-lobed petal, and 15-30 disc flowers. Both disc and ray flowers are typically bright yellow, though cream-colored flowers are known. The flower head is about 3/8 inch long and 1/4 inch wide. Click on the photo above to enlarge.
As the seeds mature they create a tiny, fluffy head. The seeds are black and sharply pointed, about 1/16 inch long. They are topped by scales that fan out from the top of the seed like spokes on a wheel.