Leaves mostly 25-50 mm, relatively even in lengths to heads. Involucres 3-3.8 mm. Ray corollas 2-3 mm. Cypselae 1-1.4 mm. 2n = 16.
Flowering (Apr-)Jun-Nov(-Dec). Gravelly, sandy, or loamy flats, rocky slopes, crevices and ledges, streambeds, creosote bush to pinyon-juniper and pine-oak-maple; (300-)600-2300(-2700) m; Ariz., N.Mex., Tex.; Mexico (Chihuahua, Coahuila, Nuevo León, Tamaulipas, San Luis Potosí); Central America (Guatemala).
Common Name: gumhead
Duration: Perennial
Nativity: Native
Lifeform: Subshrub
General: Stiffly erect shrub 50-150 cm tall, glabrous, heavily resinous, and taprooted.
Leaves: Alternate, sessile, linear or linear-lanceolate, entire, sticky, 2-5 cm long, entire margins.
Flowers: Heads radiate, in terminal corymbiform arrays; involucres cylindro-turbinate to elliptic-obovoid 3-4 mm high, sticky; phyllaries in 2-4 series, overlapping, mostly completely whitish indurate, sometimes faintly green at tips; glabrous receptacle; few ray flowers, corolla yellow 2-3 mm, tube longer than ligule; disk flowers few, corolla yellow.
Fruits: Cypselae hairy, 1-1.4 mm; pappus reduced to microscopic ring or absent.
Ecology: Found on gravelly, sandy, or loamy flats, rocky slopes, crevices and ledges, and in streambeds from 1,000-6,000 ft (305-1829 m); flowers March-December.
Distribution: s AZ, s NM, s TX; south throughout MEX, northern C. Amer. and disjunct to S. America.
Notes: Monotypic genus that is related to Gutierrezia, but recognized by being its erect, shrubby habit, sticky-resinous stems, leaves, and heads which are in dense, terminal, flat-topped arrays; differs from Gutierrezia in its being taller, larger leaves, inflorescence structure, cylindric heads, glabrous receptacles and short ray florets.
Ethnobotany: Used to treat diarrhea, rheumatism, and stomach ulcers.
Etymology: Gymnosperma comes from Greek Gymnos, for naked and sperma, seed, which refers to the epappose achene, while glutinosum means sticky.
Synonyms: Selloa glutinosa, Xanthocephalum glutinosum
Editor: SBuckley 2010, FSCoburn 2015
