Conyza ramosissima Cronquist
Family: Asteraceae
Dwarf Horseweed
[Erigeron divaricatus Michx.,  more...]
Conyza ramosissima image

Plants spreading, 5-25+ cm, branched throughout (stems usually ± strigose). Leaves: faces closely strigose; proximal blades narrowly spatulate to linear, 5-15+ × 0.5-2(-3+) mm; distal similar, smaller, narrower. Heads in loose, corymbiform arrays or borne ± singly. Involucres 3-4 mm. Phyllaries glabrous or glabrate; outer greenish to purplish, lanceolate, shorter, sparsely strigose; inner stramineous to purplish, linear-attenuate (more scarious). Receptacles 0.7-1 mm diam. in fruit. Pistillate florets 20-30; corollas ± equaling or surpassing styles, laminae 0.3-0.8 mm. Disc florets 3-8. Cypselae pale tan, 1-1.5 mm, faces sparsely strigillose or glabrous; pappi of 20-30, tawny to pinkish bristles 2-2.5 mm. 2n = 18.

Flowering late spring-early fall. Disturbed sites, usually in heavy clay soils; 100-800 m; Ala., Ark., Ill., Ind., Iowa, Kans., La., Minn., Miss., Mo., Nebr., N.Mex., N.Dak., Ohio, Okla., Pa., S.Dak., Tex., Wis.

From Flora of Indiana (1940) by Charles C. Deam

All of my specimens of this species but two were found in dry soil in pasture fields. It is avoided by grazing animals and for this reason may be detected in a field at a long distance. It prefers a sandy or prairie habitat. In Indiana there are no reports east of the counties shown on the map. My opinion is that this plant has been introduced into northern Indiana within the past 25 years.

Diffusely branched, slender, ±hairy annual 1-3 dm, with no well defined central axis; lvs narrowly linear, to 4 cm נ2 mm, the uppermost reduced to mere bracts; heads numerous, much like those of no. 1, often covering the broad, much branched summit of the plant; invol 3-4 mm, the outer bracts short-hairy, the inner glabrous; rays minute, purplish, about equaling or slightly exceeding the pappus; 2n=18. A weed in waste places, especially in sandy soil or along streams; O. and s. Ont. to Minn., s. to Ala. and Tex. Summer and fall. (Erigeron divaricatus; Leptilon d.)

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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