Perennials or subshrubs (may flower first year), 20-40+ cm. Cauline leaves mostly crowded over proximal 1/4-1/2 of plant heights, internodes mostly 5-25+ mm; lobes mostly linear to filiform, 5-25(-45+) × 0.5(-1) mm. Calyculi of 5 ovate bractlets 1-3 mm. Ray florets 0. Disc corollas yellow, sometimes with red-brown nerves, throats equal to or longer than lobes. Cypselae 2-3 mm; pappi usually 0, rarely 0.1-0.3+ mm. 2n = 40.
Flowering (Mar-)Apr-Oct. Openings in desert scrub, limestone ridges; 500-2100 m; Ariz., N.Mex., Tex.; Mexico (Coahuila, Nuevo León, San Luis Potosí, Tamaulipas).
Duration: Perennial
Nativity: Native
Lifeform: Subshrub
General: Suffrutescent perennial herbs, 20-40 cm tall, from thick, woody rootstock; stems many, branched from base; plants glabrous.
Leaves: Opposite and crowded along the lower parts of the stems; blades 3-5 cm long, pinnately divided into filiform lobes, the lobes less than 1 mm wide.
Flowers: Flower heads yellow, discoid, held well above leaves on long peduncles; involucres urceolate (urn-shaped) to hemispheric, 4-6 cm high, the phyllaries in 2 distinct series; inner phyllaries 4-6 mm high,fused together below the middle, the lobes with thin papery (scarioius) margins; outer phyllaries much smaller, 1-2 mm long, spreading; florets all discs, yellow, sometimes with red-brown nerves, the corolla lobes shorter than or equal to the thoats.
Fruits: Achenes 2-3 mm long; without a pappus or sometimes topped with 2 toothlike awns, ca. 1 mm long.
Ecology: Found in rocky soils, often in the open, often on limestone or calcareous soils, from 1,500-7,000 ft (457-2134 m); flowers March-October.
Distribution: s AZ, s NM, sw TX; south to n MEX.
Notes: Look for a perennial herb with stems and leaves that lack hairs; delicate leaves divided into threadlike lobes; and flower heads about 1 cm long or less with yellow disc flowers, and no ray flowers; the flower heads solitary on long, nearly leafless flower stalks. It appears quite similar the more common T. megapotamicum; to distinguish between the species, look at the arrangement of the leaves. T. longipes has leaves clustered near the base of the plant, while T. megapotamicum has leaves all along the stems, at least below the peduncles, though there may not be many leaves overall. Also look at the corollas of the disc florets and the seeds; T. longipes has disc corollas that are divided into lobes for less than half their length and seeds that may or may not have minute, 1-2 mm toothlike awns on top; T. megapotamicum has disc corollas which are divided into lobes for more than half their lengths and seeds with retrorsely barbed awns 2-3 mm long.
Ethnobotany: Used for tea.
Etymology: Thelesperma is from the Greek thele, nipple, and sperma seed, alluding to the papillae on the achenes of the first described species; longipes means long-stalked.
Synonyms: None
Editor: SBuckley 2010, FSCoburn 2015, AHazelton 2017
