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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

SYMPHYOTRICHUM AMERICAN-ASTER

Geraldine A. Allen


Annual or perennial herb from caudex or rhizome. Stem: generally erect, 1–24 dm. Leaf: basal and/or cauline, alternate, generally entire; basal generally petioled. Inflorescence: heads generally radiate, 1 or in cyme- or panicle-like cluster; involucre cylindric to hemispheric; phyllaries graduated or ± equal in 2–6 series, at least inner proximally with pale, papery margins; receptacle ± flat, pitted, epaleate. Ray flower: [8]14–100+; corolla violet to pink or white. Disk flower: 4–60+; corolla, anthers generally yellow, tube generally < throat; anther tip ± triangular; style branches flat on inner face, base ± warty, tip acute, hairy. Fruit: generally rounded, ± ribbed, ± brown; pappus of bristles, white to ± brown.
± 90 species: North America, South America, eastern Eurasia. (Greek: bristle hair) [Brouillet et al. 2006 FNANM 20:465–539] Reported records of Symphyotrichum laeve (L.) G.L. Nesom var. geyeri (A. Gray) G.L. Nesom from Del Norte Co. are Symphyotrichum subspicatum (Nees) G.L. Nesom.
Unabridged references: [Nesom 1994 Phytologia 77:141–297]

Key to Symphyotrichum

1. Annual, taprooted; ray corolla < 8 mm, generally > disk flowers by 2 mm or less

2. Ray flowers 90–110, rays <= 0.2 mm wide; disk flowers > 35; phyllaries obtuse to rounded; leaves elliptic to obovate, ± obtuse ..... S. frondosum

2' Ray flowers 21–54, rays >= 0.2 mm wide; disk flowers 7–23; phyllaries acute to acuminate; leaves linear to oblanceolate, obtuse to acute ..... S. subulatum

3. Ray corolla pink to lavender, generally 2.5–3.5 mm, drying in 2–3 coils; ray flowers >= 30, disk flowers 11–23 ..... var. elongatum

3' Ray corolla generally white to pink, 1.3–3 mm, drying in 1–2 coils or curling; ray flowers 27–40, disk flowers 7–15

4. Phyllaries > 30; pappus bristles generally 3.5–4 mm, < ray corollas ..... var. parviflorum

4' Phyllaries < 30; pappus bristles generally 4.0–5.2 mm, > ray corollas ..... var. squamatum

1' Perennial herb, generally from rhizome or caudex; ray corolla 6–12 mm, conspicuous

5. Involucre ± glandular — peduncle ± glandular ..... S. campestre

5' Involucre glabrous to ± hairy, not glandular

6. Outer phyllaries obtuse to rounded, < inner ones, ± pale-margined at base, with green area at tip generally < 2.5 × longer than wide; stem generally densely and uniformly strigose, especially below heads

7. Inflorescence open, branches generally > 5 cm; leaves glabrous to ± strigose, generally lacking short leafy shoots in axils; stem 2–6 dm ..... S. ascendens

7' Inflorescence narrow, branches generally < 5 cm; leaves strigose, generally with short leafy shoots in axils; stem 4–10 dm ..... S. defoliatum

6' Outer phyllaries acute to obtuse, <= inner ones, green throughout, or ± pale-margined at base with green area at tip generally > 2.5 × longer than wide; stem ± glabrous to ± hairy distally or with hairs generally ± in lines

8. Leaves rough-hairy on faces, elliptic to obovate, cauline > basal; phyllaries acute ..... S. greatae

8' Leaves glabrous to ± soft-hairy, generally ± linear to narrowly elliptic (if wider, basal > cauline); phyllaries acute to obtuse

9. Leaves ± equal or mid-cauline largest, basal generally 0 at flower; ray white to pink or violet; < 2000 m

10. Outer phyllaries pale-margined > 1/2 length, length generally 3+ × width

11. Stem ± hairy in lines; leaves lanceolate; inflorescence bracts well developed ..... S. lanceolatum var. hesperium

11' Stem ± glabrous; leaves linear to narrowly lanceolate; inflorescence bracts small ..... S. lentum

10' Outer phyllaries pale-margined < 1/2 length, length generally < 3 × width

12. Ray generally pink to white; inflorescence generally narrow, lateral branches generally < 10 cm; phyllaries generally ± equal ..... S. bracteolatum

12' Ray violet; inflorescence generally open, lateral branches generally 10+ cm; outer phyllaries generally < inner

13. Outer phyllaries obtuse ..... S. chilense

13' Outer phyllaries ± acute ..... S. subspicatum

9' Basal or proximal cauline leaves largest, basal generally present at flower; ray violet to purple; > 1000 m

14. Stem 7–15 dm; cauline leaves elliptic to oblanceolate base lobed, clasping; heads > 35; phyllaries ± pale-margined at base ..... S. hendersonii

14' Stem 0.5–8 dm; cauline leaves linear to narrowly elliptic or heads < 35; phyllaries pale-margined at base or outermost green throughout

15. Leaves < 7 × longer than wide; outermost phyllaries generally green throughout, ± = inner ..... S. foliaceum

16. Heads 1(2–4); stem 0.5–2 dm; phyllaries ± purple-tinged ..... var. apricum

16' Heads 1–12 (generally > 1); stem 1–4 dm; phyllaries green ..... var. parryi

15' Leaves 7+ × longer than wide; outermost phyllaries pale-margined at base, < inner ..... S. spathulatum

17. Leaves ± linear ..... var. yosemitanum

17' Leaves lanceolate to narrowly elliptic

18. Stem 4–8 dm, heads generally 10–50 ..... var. intermedium

18' Stem 2–6 dm, heads generally 3–10 ..... var. spathulatum

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Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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