Plants 4-60 cm. Leaf blades 7-110 × 3-70(-80) mm. Peduncles 1-40 mm. Involucres campanulate, 2.5-5 mm diam. Phyllaries persistent. Paleae: outer persistent with distal phyllaries or falling, elliptic to obovate; inner usually persistent, lanceolate to ovate or obovate, 2-3.5 mm, 3-lobed, lobes to 1/3+ total lengths, acute. Ray florets (3-)5(-8); corollas usually dull white (pink), laminae 0.5-1.8 × 0.7-1.5 mm. Disc florets 15-50. Cypselae: rays 1.5-2.5 mm; discs 1.3-2.5 mm, glabrous or strigose; pappi: rays 0 or of 5-10, laciniate scales 0.5-1 mm; discs 0, or of 15-20 white or gray, linear, fimbriate, obtuse (acute) scales 0.5-2 mm.
Much like no. 1 [Galinsoga quadriradiata Ruiz & Pav.], less hairy, the stem glabrous or sparsely pubescent with appressed or sometimes spreading hairs, the peduncles appressed-hairy, or finely villous with spreading, gland-tipped hairs; lvs ovate or lance-ovate, mostly less coarsely toothed; outer invol bracts 2-4, scarious-margined, persistent, the inner ones and their attached pales also persistent; inner receptacular bracts deeply trifid; achenes sparsely appressed-hairy or glabrous; pappus scales of the disk-fls conspicuously fimbriate, generally blunt, nearly or quite as long as the cor; rays to 1.5(-2) mm, nearly or quite epappose; 2n=16. Native from sw. U.S. to S. Amer., but now a cosmopolitan weed.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
FNA 2006, Kearney and Peebles 1969, McDougall 1973, USDA Plants
Duration: Annual Nativity: Non-Native Lifeform: Forb/Herb General: Herbaceous annuals, to 60 cm tall, with slender stems. Leaves: Opposite, narrowly lanceolate or the lower ones ovate, petioled, with toothed margins. Flowers: Heads small, radiate, rays white or rarely pink, 4-5, only slightly surpassing the disk, disk flowers yellow, perfect, heads campanulate, 3-4 mm high, receptacles conic, with few phyllaries, these broad, and membranaceous, with several green nerves, each phyllary subtending a ray flower, inflorescences cymose. Fruits: Achenes 4-angled. The pappus of the ray flowers reduced or lacking, the pappus of the disk flowers of approximately 20 palea, nearly as long as the disk corollas. Ecology: Found on rich soils in mountainous areas in the shade, from 5,500-8,000 ft (1676-2438 m); flowering September-October. Distribution: Widespread throughout the United States, including, Arizona, California, New Mexico, and Texas; Mexico. Notes: Look for this species under Galinsoga semiclava in older texts. This appears to be the only species of this genus in Arizona. Ethnobotany: Unknown Etymology: Galinsoga is named for Mariano Martinez de Galinsoga (1766-1797) who headed the Madrid Botanical garden, while parviflora means small-flowered. Synonyms: Galinsoga parvifloa var. semicalva, G. semicalva, G. semicalva var. percalva Editor: LCrumbacher 2011