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FNA | Family List | FNA Vol. 20 | Asteraceae



Guy L. Nesom

Achaetogeron A. Gray; Trimorpha Cassini











Key to Groups of Erigeron Species

1 Heads discoid or disciform (pistillate florets 0 or their corollas filiform, lacking laminae)   Group 1
+ Heads radiate (corollas of pistillate florets bearing laminae, laminae sometimes filiform and hardly surpassing involucres, especially Groups 8 and 11)   (2)
2 (1) Plants with herbaceous, leafy runners or slender, scale-leaved rhizomes.   Group 2
+ Plants without leafy runners or scale-leaved rhizomes   (3)
3 (2) Leaves pinnately lobed or dissected   Group 3
+ Leaves usually entire or dentate, rarely with 1–2 pairs of coarse lobes   (4)
4 (3) Annuals, biennials, or short-lived perennials   (5)
+ Perennials   (9)
5 (4) Pappus bristles absent on ray and/or disc cypselae   Group 4
+ Pappus bristles present on ray and disc cypselae   (6)
6 (5) Ray laminae nearly filiform, erect   (7)
+ Ray laminae strap-shaped, usually spreading   (8)
7 (6) Heads usually in loose, racemiform arrays; pistillate florets in 1 series, all with filiform laminae; pappus bristles not accrescent   114 Erigeron lonchophyllus
+ Heads usually in corymbiform arrays; pistillate florets in 2 zones, outer with nearly filiform laminae, inner tubular and essentially elaminate; pappus bristles accrescent (elongating in fruit to ca. 2 times involucres)   Group 8 (in part)
8 (6) Plants fibrous-rooted   Group 5
+ Plants taprooted   Group 6
9 (4) Leaves 3-lobed or 3-dentate at apices; plants usually with relatively slender, rhizomelike caudex branches (rarely in E. compositus)   Group 7
+ Leaves not 3-lobed or 3-dentate at apices; plants with or without slender caudex branches   (10)
10 (9) Pistillate florets in 2 zones, outer with nearly filiform, erect laminae, sometimes shorter than involucres, inner tubular and essentially elaminate; pappus bristles accrescent (elongating in fruit to ca. 2 times involucres)   Group 8 (in part)
+ Pistillate florets all with strap-shaped, spreading laminae, occasionally reduced, nearly filiform and erect (in some arctic, monocephalous species); pappus bristles not accrescent (except in E. uniflorus var. eriocephalus).   (11)
11 (10) Rays yellow   Group 9
+ Rays white or blue to pink   (12)
12 (11) Plants fibrous-rooted (usually rhizomatous, rhizomes sometimes abbreviated or apparently lacking in E. glabellus) or without an evident taproot (taproot weakly developed or not collected because of extensive rhizome or caudex system)   (13)
+ Plants usually evidently taprooted (sometimes also with branched caudices)   (16)
13 (12) Rhizomes or caudex branches slender (without apparent well-defined central axes); ray laminae strap-shaped   Group 10
+ Rhizomes thickened (usually evident as single central axes; abbreviated or apparently lacking in E. glabellus); ray laminae filiform or strap-shaped   (14)
14 (13) Basal and proximal cauline leaves reduced or present only as scales (cauline largest at midstem); ray laminae not coiling; cypselae 5–6-nerved, glabrous   2 Erigeron hyssopifolius (in part)
+ Basal and proximal cauline leaves usually well developed (sometimes withering by flowering); ray laminae usually coiling, often tardily or only at tips (filiform and straight in some species of Group 11); cypselae mostly 2(–4)-nerved (4–7-nerved in E. glacialis and E. howellii), usually strigose   (15)
15 (14) Plants 2–25(–35) cm; leaves mostly basal (bases of cauline not clasping orsubclasping); heads 1–3   Group 11
+ Plants (5–)15–90 cm; leaves basal and cauline or mostly cauline (bases ofcauline usually clasping to subclasping); heads 1–21   Group 12
16 (12) Perennials (short-lived), caudices usually not branched (stems and leaves arisingfrom near roots)   Group 13
+ Perennials, caudices usually branched   (17)
17 (16) Leaves all or mostly cauline (basal not markedly larger than cauline, internodes relatively short), blades linear or filiform to narrowly oblong, essentially uniform; California and immediately adjacent areas   Group 14
+ Leaves mostly basal or basal and cauline (if basal withering by flowering, then persistent leaf bases usually evident), oblanceolate, obovate, or spatulate (if linear or filiform then basal larger than cauline and internodes relatively wide); w North America   (18)
18 (17) Proximal leaves loosely clustered (not in persistent rosettes, usually with evident internodes), blades oblanceolate or linear to filiform; stems and leaves ± strigose   (19)
+ Proximal leaves tightly clustered (usually in persistent rosettes, internodes not readily evident), blades 1- or 3-nerved, linear to oblanceolate, obovate, or spatulate; stems and leaves strigose to hirsute, villous, or lanate-villous   (20)
19 (18) Plants 20–70 cm; leaves oblanceolate; pappi readily falling, of (8–)10–12 bristles; stems not more densely hairy proximally than distally   3 Erigeron neomexicanus (in part)
+ Plants 10–30(–50) cm; leaves linear to filiform; pappi persistent, of 20–30 bristles; stems more densely white-strigose proximally than distally (hairs loosely appressed to ascending, fine)   53 Erigeron filifolius (in part)
20 (18) Basal leaves obovate-spatulate, 5–25 mm wide, cauline little reduced distally or relatively even-sized, bases usually subclasping (except in E. oreganus); heads usually 1, sometimes 2–5 from proximal axils   Group 17
+ Basal leaves linear to oblanceolate or spatulate, (0.5–)1–13(–15) mm wide, cauline usually gradually or abruptly reduced distally, bases not clasping or subclasping; heads 1–16   (21)
21 (20) Petioles prominently ciliate (hairs spreading, thick-based); leaves mostly linear to narrowly oblanceolate   (22)
+ Petioles not prominently ciliate (or if so, hairs thin-based or ascending to loosely appressed); leaves linear to obovate or spatulate   (23)
22 (21) Leaves basal and cauline or sometimes mostly basal; heads 1–5; ray laminae reflexing (coiling in E. davisii, added to key for contrast with E. engelmannii)   Group 15
+ Leaves mostly basal; heads 1; ray laminae sometimes coiling, not reflexing   Group 16
23 (21) Stems and leaves glabrous or glabrate (minutely glandular in E. nauseosus, sometimes minutely glandular distally in E. arenarioides); phyllaries minutely glandular, rarely also sparsely strigose or hirsuto-villous (sometimes glabrous, eglandular), often purplish; ray laminae reflexing, coiling, or straight and spreading   Group 18
+ Stems and/or leaves strigose or sericeous to hirsute or villous; phyllaries strigose to hirsute, sometimes glandular, rarely purplish; ray laminae coiling or straight and spreading (reflexing in E. parishii and E. canus)   (24)
24 (23) Stems with spreading hairs   Group 19
+ Stems with appressed hairs   (25)
25 (24) Stems ascending to decumbent, sometimes purplish proximally; basal leaves (1–)3-nerved, usually linear to oblanceolate, sometimes obovate; stems and leavesstrigose to hirsute   Group 20
+ Stems mostly erect, usually not purplish proximally; basal leaves linear to oblanceolate or spatulate; stems and leaves usually strigose or sericeous (hairs usually whitish, closely appressed, even-length)   (26)
26 (25) Leaves mostly spatulate   Group 21
+ Leaves linear to oblanceolate   (27)
27 (26) Leaf bases of basal and proximal cauline leaves abruptly widened, thickened, and white-indurate   Group 22
+ Leaf bases sometimes widened, not thickened and white-indurate   Group 23

List of Keys

  • List of lower taxa


    Related Objects  

    Flora of Chile  
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