Hymenoxys odorata Dc.
Family: Asteraceae
bitter rubberweed,  more...
[Actinella odorata ,  more]
Hymenoxys odorata image
Patrick Alexander  
Annuals, 10-80 cm (robust). Stems 1-25, usually purple-red-tinted proximally, sometimes throughout, often branched throughout, ± hairy. Leaves: blades simple or lobed (lobes 3-19+), ± hairy, gland-dotted; mid leaves lobed (lobes 5-11+, terminal lobes 0.3-1 mm wide). Heads 15-350+ per plant in paniculiform arrays. Peduncles 2-12 cm, sparsely hairy. Involucres subhemispheric to campanulate to ± urceolate, 6-10 × 7-12.5 mm. Phyllaries in 2 series, unequal; outer 8-13, basally connate 1/4-1/3 their lengths, obovate to oblanceolate, 3.5-5.2 mm, apices acuminate; inner 8-13, obovate, 3.8-5.9 mm, apices acuminate to acute. Ray florets 8-13; corollas yellow, 8.5-11 × 3-5.5 mm. Disc florets 50-150+; corollas 2.6-4.1 mm. Cypselae narrowly obpyramidal, 1.7-2.5 mm; pappi of 5-6 obovate, aristate scales 1.6-2.3 mm. 2n = 22, 24, 28, 30. Flowering (Feb-)Apr-Jun(-Aug). Roadsides, open flats, mesquite and creosote-bush flats, ditches and drainage areas, stream banks and bottoms; 60-1500 m; Ariz., Calif., Colo., Kans., N.Mex., Okla., Tex.; Mexico (Chihuahua, Coahuila, Durango, Nuevo León, San Luis Potosí, Sonora, Tamaulipas).
FNA 2006, Alonso-Castro 2011, Heil et al. 2013, MacDougall 1973
Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Annual herbs, 15-60 cm tall, bushy and aromatic, from a taproot; stems 1-25, usually purple-red-tinted proximally, sometimes throughout, often branched throughout, more or less hairy. Leaves: Basal leaved usually withered by flowering; caluine leaves alternate; blades 1-10 cm long, pinnately lobed into 3-15 filiform segments, more or less hairy, gland-dotted. Flowers: Heads radiate and yellow, in panicles of 15-350+ flower heads, on sparsely hairy peduncles; involucres subhemispheric to campanulate or urceolate, 6-10 mm high and 7-12 mm wide; phyllaries in 2 unequal series, the outer series united at the base for the 1/4 to 1/3 of their lengths, obovate to oblanceolate, 3-5 mm long; inner series of phyllaries not united at the base, obovate, 4-6 mm long; ray florets 8-13 per flower head, the laminae (ray petals) 8-11 mm long, yellow; disc florets 50-150+ per flower head, yellow. Fruits: Achenes narrowly obpyramidal, 2 mm long; topped with a pappus of 5-6 obovate, aristate scales, 2 mm long. Ecology: Found on roadsides, open flats, mesquite and creosote-bush flats, ditches and drainage areas, stream banks and bottoms, below 5,000 ft (1524 m); flowers (Feb-) Apr- June (-Aug). Distribution: AZ, CA., CO., KS., NM, OK, and TX; south to MEX Notes: Distinguished by being a robust annual herb branching throughout; leafy to densely leafy foliage of thinly divided, gland-dotted, sparsely hairy leaves with narrow, pointed lobes; yellow disks and white-yellow 3-lobed rays; hairy seeds resembling an inverted pyramid topped with a pappus of 5-6 broadening scales with pointed tips. Becomes abundant in overused rangeland; highly poisonous to livestock. It is noted to be pleasantly aromatic. Ethnobotany: Used medicinally by indigenous tribes; a secondary compound, hymenovin, has been found to have anti-cancer properties. Etymology: Hymenoxys comes from Greek hymen, meaning membrane, and oxys, meaning sharp or sharp pointed, referring to the awned pappus scales; odorata means possessing an odor. Synonyms: Picradenia odorata, Hymenoxys chrysanthemoides subsp. osterhoutii, Hymenoxys multiflora Editor: FSCoburn 2014, AHazelton 2017
Hymenoxys odorata image
Patrick Alexander  
Hymenoxys odorata image
Patrick Alexander  
Hymenoxys odorata image
Patrick Alexander  
Hymenoxys odorata image
Patrick Alexander  
Hymenoxys odorata image
Patrick Alexander  
Hymenoxys odorata image
Patrick Alexander  
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Sue Rutman  
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image
Hymenoxys odorata image