1	"Annual, taprooted; ray corolla < 8 mm, generally > disk flowers by 2 mm or less"	2
1	"Perennial herb, generally from rhizome or caudex; ray corolla 6--12 mm, conspicuous"	5
2	"Ray flowers 90--110, rays <= 0.2 mm wide; disk flowers > 35; phyllaries obtuse to rounded; leaves elliptic to obovate, +- obtuse"	"Symphyotrichum 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"	3
3	"Ray corolla pink to lavender, generally 2.5--3.5 mm, drying in 2--3 coils; ray flowers >= 30, disk flowers 11--23"	"Symphyotrichum subulatum 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
4	"Phyllaries > 30; pappus bristles generally 3.5--4 mm, < ray corollas"	"Symphyotrichum subulatum var. parviflorum"
4	"Phyllaries < 30; pappus bristles generally 4.0--5.2 mm, > ray corollas"	"Symphyotrichum subulatum var. squamatum"
5	"Involucre +- glandular --- peduncle +- glandular"	"Symphyotrichum campestre"
5	"Involucre glabrous to +- hairy, not glandular"	6
6	"Outer phyllaries obtuse to rounded, < inner ones, +- pale-margined at base, with green area at tip generally < 2.5 &times; longer than wide; stem generally densely and uniformly strigose, especially below heads"	7
6	"Outer phyllaries acute to obtuse, <= inner ones, green throughout, or +- pale-margined at base with green area at tip generally > 2.5 &times; longer than wide; stem +- glabrous to +- hairy distally or with hairs generally +- in lines"	8
7	"Inflorescence open, branches generally > 5 cm; leaves glabrous to +- strigose, generally lacking short leafy shoots in axils; stem 2--6 dm"	"Symphyotrichum ascendens"
7	"Inflorescence narrow, branches generally < 5 cm; leaves strigose, generally with short leafy shoots in axils; stem 4--10 dm"	"Symphyotrichum defoliatum"
8	"Leaves rough-hairy on faces, elliptic to obovate, cauline > basal; phyllaries acute"	"Symphyotrichum greatae"
8	"Leaves glabrous to +- soft-hairy, generally +- linear to narrowly elliptic (if wider, basal > cauline); phyllaries acute to obtuse"	9
9	"Leaves +- equal or mid-cauline largest, basal generally 0 at flower; ray white to pink or violet; < 2000 m"	10
9	"Basal or proximal cauline leaves largest, basal generally present at flower; ray violet to purple; > 1000 m"	14
10	"Outer phyllaries pale-margined > 1/2 length, length generally 3+ &times; width"	11
10	"Outer phyllaries pale-margined < 1/2 length, length generally < 3 &times; width"	12
11	"Stem +- hairy in lines; leaves lanceolate; inflorescence bracts well developed"	"Symphyotrichum lanceolatum var. hesperium"
11	"Stem +- glabrous; leaves linear to narrowly lanceolate; inflorescence bracts small"	"Symphyotrichum lentum"
12	"Ray generally pink to white; inflorescence generally narrow, lateral branches generally < 10 cm; phyllaries generally +- equal"	"Symphyotrichum bracteolatum"
12	"Ray violet; inflorescence generally open, lateral branches generally 10+ cm; outer phyllaries generally < inner"	13
13	"Outer phyllaries obtuse"	"Symphyotrichum chilense"
13	"Outer phyllaries +- acute"	"Symphyotrichum subspicatum"
14	"Stem 7--15 dm; cauline leaves elliptic to oblanceolate base lobed, clasping; heads > 35; phyllaries +- pale-margined at base"	"Symphyotrichum 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
15	"Leaves < 7 &times; longer than wide; outermost phyllaries generally green throughout, +- = inner"	16
15	"Leaves 7+ &times; longer than wide; outermost phyllaries pale-margined at base, < inner"	17
16	"Heads 1(2--4); stem 0.5--2 dm; phyllaries +- purple-tinged"	"Symphyotrichum foliaceum var. apricum"
16	"Heads 1--12 (generally > 1); stem 1--4 dm; phyllaries green"	"Symphyotrichum foliaceum var. parryi"
17	"Leaves +- linear"	"Symphyotrichum spathulatum var. yosemitanum"
17	"Leaves lanceolate to narrowly elliptic"	18
18	"Stem 4--8 dm, heads generally 10--50"	"Symphyotrichum spathulatum var. intermedium"
18	"Stem 2--6 dm, heads generally 3--10"	"Symphyotrichum spathulatum var. spathulatum"