Erigeron tenuis |
Erigeron tracyi |
|
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slender fleabane, slender-leaf fleabane |
running fleabane |
|
Habit | Biennials or short-lived perennials, 10–45 cm; fibrous-rooted, caudices simple. | Annuals, biennials, or short-lived perennials, 2.5–8(–12, 18) cm; usually taprooted, sometimes fibrous-rooted, caudices simple or branched. |
Stems | ascending (usually reddish proximally, branched distally), strigose, rarely hirsute proximally, eglandular. |
first erect (greenish proximally), then producing herbaceous, leafy, prostrate runners (stoloniform branches, sometimes with rooting plantlets at tips), densely hirsutulous (hairs spreading-deflexed, of relatively even lengths and orientations), sparsely minutely glandular. |
Leaves | basal (commonly persistent) and cauline; basal blades oblanceolate to obovate or spatulate, 20–100(–130) × 4–20 mm, margins serrate or crenate to pinnately lobed, faces sparsely hirsute to strigoso-hirsute (hairs ascending), eglandular; cauline becoming narrower and entire (bases not clasping or subclasping), abruptly reduced near midstem. |
mostly basal (persistent in early season); blades oblanceolate to spatulate (obovate-elliptic laminae), 10–30(–60) × 3–6(–12) mm, cauline abruptly reduced distally, margins entire, dentate, or lobed, faces densely hirsute, eglandular. |
Involucres | (2–)2.5–4 × 5–10 mm. |
3.5–4.5(–6) × 6–9(–12) mm. |
Ray florets | 60–120; corollas blue to pale lavender or white, drying blue to purplish, 3–5 mm, laminae not coiling or reflexing. |
60–130; corollas white, often purplish abaxially, sometimes with an abaxial midstripe, 5–9 mm, laminae not coiling or reflexing. |
Disc corollas | 2–2.7 mm. |
2–3 mm (throats indurate and slightly inflated). |
Phyllaries | in 2–4 series, sparsely strigose, eglandular. |
in 3–4 series, sparsely to moderately hirsute, minutely glandular. |
Heads | (1–)3–20(–60) in loosely corymbiform arrays (usually from branches beyond midstem). |
1(–3 rarely, from midstem or proximal branches). |
Cypselae | 1–1.2 mm, 2(–4)-nerved, faces sparsely strigose; pappi: outer of setae, inner of 11–15 bristles. |
0.7–1.3 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of 12–16 bristles. |
2n | = 27. |
|
Erigeron tenuis |
Erigeron tracyi |
|
Phenology | Flowering mid Mar–May(–Jun, –Nov). | Flowering Mar–Oct. |
Habitat | Open oak, oak-pine, or pine woodlands, roadsides, fencerows, pastures, bottomland, sand or sandy clay, less common in clay | Desert scrub, grassy slopes, oak chaparral, pinyon-juniper woodlands, Douglas fir-ponderosa pine |
Elevation | 10–200 m (0–700 ft) | 700–2300(–2400) m (2300–7500(–7900) ft) |
Distribution |
AL; AR; FL; KS; LA; MO; MS; OK; TX
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AZ; CO; KS; NM; NV; OK; TX; UT; Mexico (Baja California, Chihuahua, Coahuila, Durango, Sonora, Zacatecas)
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Discussion | A plant reported as Erigeron tenuis disjunct in North Carolina is perhaps better identified as E. strigosus: pappus bristles on the ray cypselae are reduced and variable in number. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
In March through June, plants of Erigeron tracyi produce leaves in a basal rosette usually with a single, erect, monocephalous, stem. Stoloniform branches are soon formed (often recognized on pressed specimens by the leaves mostly on one side of the branches), and by the end of the season (August through October), prostrate runners are usually evident, sometimes forming terminal, rooting plantlets. Erigeron tracyi is similar in habit to E. flagellaris, particularly in the herbaceous stolons or stoloniform branches; the stem pubescence of E. tracyi is different, the stolons much less commonly produce rooting plantlets at the tips, and the plants tend to be perennial with woody or lignescent caudices, although they are variable both in habit and duration. Apparent hybrids with E. modestus and E. flagellaris are occasionally encountered, and the most common form of E. tracyi is perhaps (speculative) a stabilized, apomictic hybrid between the latter and E. divergens. All chromosome counts thus far have shown E. tracyi to be triploid and asynaptic. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 347. | FNA vol. 20, p. 340. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. cinereus, E. colomexicanus, E. commixtus, E. divergens var. cinereus | |
Name authority | Torrey & A. Gray: Fl. N. Amer. 2: 175. (1841) | Greene: Pittonia 5: 59. (1902) |
Web links |