Erigeron hyssopifolius |
Erigeron tracyi |
|
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hyssop-leaf fleabane, vergerette à feuilles d'hysope |
running fleabane |
|
Habit | Perennials, 5–35 cm; rhizomatous, fibrous-rooted, caudices sometimes branched. | Annuals, biennials, or short-lived perennials, 2.5–8(–12, 18) cm; usually taprooted, sometimes fibrous-rooted, caudices simple or branched. |
Stems | erect, sparsely and loosely strigose to strigoso-villous, 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 and proximal cauline much reduced or present as scales; cauline blades linear to linear-oblong or oblong-lanceolate, 10–30 × 1–5 mm, largest at midstem, then relatively even-sized to peduncles, margins entire, sometimes prominently ciliate, faces glabrous or sparsely villous. |
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 | 4–6 × 6–12 mm. |
3.5–4.5(–6) × 6–9(–12) mm. |
Ray florets | 20–50; corollas white, less commonly pinkish, or aging pinkish, 4–8 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 | 3–4.6 mm. |
2–3 mm (throats indurate and slightly inflated). |
Phyllaries | in 2–3 series, loosely and sparsely strigose, eglandular. |
in 3–4 series, sparsely to moderately hirsute, minutely glandular. |
Heads | 1(–5). |
1(–3 rarely, from midstem or proximal branches). |
Cypselae | 1.3–1.6 mm, 5–6-nerved, faces glabrous; pappi: outer of setae, inner of 25–35 bristles. |
0.7–1.3 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of 12–16 bristles. |
2n | = 18. |
= 27. |
Erigeron hyssopifolius |
Erigeron tracyi |
|
Phenology | Flowering Jun–Aug. | Flowering Mar–Oct. |
Habitat | Open woods, river gravel, rock ledges and crevices, gravel barrens, roadsides | Desert scrub, grassy slopes, oak chaparral, pinyon-juniper woodlands, Douglas fir-ponderosa pine |
Elevation | 0–500 m (0–1600 ft) | 700–2300(–2400) m (2300–7500(–7900) ft) |
Distribution |
ME; MI; NH; NY; VT; AB; MB; NB; NF; NS; NT; NU; ON; QC; SK; YT
|
AZ; CO; KS; NM; NV; OK; TX; UT; Mexico (Baja California, Chihuahua, Coahuila, Durango, Sonora, Zacatecas)
|
Discussion | Variety villicaulis, from Anticosti Island (Quebec) and Newfoundland, has been distinguished on the basis of its relatively shorter stature (mostly 3–15 cm) and greater ratio of peduncle to leafy-stem lengths (stems and peduncles as long as or longer than the leafy parts of stems); the distinction appears to be arbitrary. (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. 277. | FNA vol. 20, p. 340. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. hyssopifolius var. anticostensis, E. hyssopifolius var. villicaulis | E. cinereus, E. colomexicanus, E. commixtus, E. divergens var. cinereus |
Name authority | Michaux: Fl. Bor.-Amer. 2: 123. (1803) | Greene: Pittonia 5: 59. (1902) |
Web links |