Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.
Copy permalink to share | Check for keys that lead to this key
1 Mid-stem leaves linear to lanceolate; stem usually straight (lacking bends alternating at the nodes). | |
2 Phyllaries appressed, apices acute to acuminate (also keyed in Key F); plants 1.5-4 (-6) dm; [ultramafic outcrop barrens, Clay co., NC]; [series Punicei] | |
2 Phyllaries spreading; plants (1.7-) 6-25+ dm; [other habitats, collectively widespread]. | |
3 Phyllaries mostly obtuse to acute, sometimes acuminate, green zones foliaceous; mid and upper stem leaves mostly lanceolate or oblanceolate to linear, faces glabrous, bases slightly auriculate-clasping to short-petiolate and attenuate; stems sparsely hairy in lines above, otherwise glabrous; [series Symphyotrichum]. | |
5 Leaves linear, > 10× as long as wide; leaf bases only subclasping | |
3 Phyllaries mostly long-acuminate to caudate; mid and upper stem leaves mostly ovate, obovate, lanceolate, or oblanceolate, scabrous adaxially (except S. firmum), bases strongly auriculate-clasping (except S. elliottii); stems densely hispid to sparsely hairy in lines; [series Punicei]. | |
7 Stems glabrous, occasionally hispidulous in lines; abaxial cauline leaf midvein glabrous; capitulescence dense, leafy; heads with white to pale lavender
ray florets; shoots arising singly from elongate rhizomes | |
7 Stems densely pubescent, usually purplish; abaxial cauline leaf midvein moderately to densely pubescent; capitulescence widely spreading and heads with
lavender to purple ray florets; shoots often found in clumps of 2-6 arising
from a persistent stout caudex | |
Copy permalink to share | Check for keys that lead to this key
1 Mid and upper stem leaves mostly linear or linear-lanceolate, nearly parallel-sided or narrowed from near strongly auriculate-clasping base; ray blades (7-) 10-15 (-20) mm; stems and leaf faces glabrous | |
2 Plants annuals, from a taproot, glabrous; involucres narrowly turbinate or cylindro-turbinate (in bloom, broadened from peduncle to apex); inflorescence open and diffuse, bracts subulate, appressed-ascending, and inconspicuous; stem leaves attenuate with strongly sheathing petioles; [subgenus Astropolium] | |
2 Plants perennials, rhizomatous or from branched caudices, usually pubescent at least in lines on stems or along leaf veins; involucres more or less campanulate (contracted above middle, less commonly cylindric); inflorescence various, bracts foliaceous (subulate in some forms of S. dumosum); stem leaves sheathing or not. | |
3 Stem leaves (below arrays) oblanceolate-elliptic or oblong-lanceolate, auriculate-clasping; inflorescences open, sparsely bracteate (bracts mostly 1-3 per peduncle, foliaceous), leaves and bracts much reduced in arrays; plants 1.5-4 (-6) dm tall; [ultramafic outcrop barrens, Clay co., NC]; [subsection Symphyotrichum, series Punicei] | |
3 Stem leaves various, not auriculate clasping; inflorescences leafy, often crowded, leaves and bracts gradually reduced (or bracts abruptly reduced, but 5-15+ per peduncle); plants (0.5-) 3-15 dm tall; [widespread in a variety of habitats] | |
4 Peduncles long (usually many on plant > 2 cm long), with copious (5-15+) small, closely-spaced, oblong or linear-subulate bracts mostly 1-4 mm long, abruptly smaller than the stem and branch leaves; plants single or somewhat cespitose (rhizomes short); phyllary apices acute to obtuse, green zones broadened near apex (oblanceolate or diamond-shaped). | |
5 Leaves and bracts thick, firm; bracts abruptly reduced from stem leaves, oblong to linear-subulate; involucres (3-) 4.5-6.3 mm, cylindro-campanulate. | |
6 Upper stems and array branches moderately to densely hirtellous; adaxial faces of upper stem and branch leaves strigoso-scabrous; phyllaries and bracts usually prominently mucronate; plants usually sparsely stipitate-glandular in arrays; [May Prairie, TN]; [subgenus Virgulus] | |
6 Upper stems and array branches strigose, mostly in lines; adaxial faces of upper stem and branch leaves glabrous to scabrous; plants eglandular; [widespread]. | |
8 Cauline leaves 3-7 cm long; branches few; peduncles long; rays 14-17 (-20) | |
8 Cauline leaves to 15 cm long; branches abundant; peduncles long, short, or absent; rays 13-25. | |
9 Stems glabrate, puberulent, or strigose; branches crowded; most peduncles short to absent, their bracts not uniform, some long and narrow. | |
10 Stems glabrate, scabrous-puberulent, or strigose with coarse hairs; inflorescence diffuse; rays 20-25 | |
4 Peduncles short (< 2 cm long), bracts gradually reduced, foliaceous; plants strongly colonial from creeping rhizomes (except S. lateriflorum and S. tradescantii); phyllary apices various, acuminate with longer or less distinct green zones in many species. | |
11 Upper stems, array branches, and both faces of leaves strigoso-scabrous or hirtellous (short, stiff, spreading hairs), usually densely so; plants usually stipitate-glandular distally (on upper stems, array branches, and leaves); leaves and bracts firm, stiffly spreading, sessile. | |
12 Leaf venation conspicuously reticulate, forming isodiametric areoles; leaf margins revolute; plants 5-15dm, arrays typically densely pyramidal with numerous, dense, often subsecund branches; [widespread] | |
12 Leaf areoles elongate and indistinct; leaf margins not revolute; plants 3-9dm, arrays loosely paniculiform; [FL]; [subgenus Virgulus] | |
13 Leaf veinlets conspicuously reticulate, forming isodiametric areoles visible on the lower surface; leaves waxy on upper surface (at least when young), the margins usually revolute and entire or weakly toothed; peduncle bracts 5-12 on well-developed peduncles, foliaceous, crowded, closely subtending and often partially obscuring involucres; ray flowers lavender or purple. | |
15 Stem puberulent in lines above; lower leaf surface subglabrous to sparsely scabrous-puberulent; [widespread west of the Appalachians] | |
15 Stem spreading puberulent throughout; lower leaf surface moderately to densely spreading-puberulent; [MO, AR, and LA westward] | |
17 Leaves thick, firm, margins recurved; involucres (4.5-) 6-8 mm; rays usually pale lavender or lilac; [coastal plain, NC south to FL and AL]. | |
18 Leaves narrowly lanceolate, serrate; plants to 15 dm tall; [wetland and upland habitats, NC to s. FL, west to s. AL] | |
17 Leaves thin, margins planar or (S. racemosum, S. eulae) recurved; involucres 3-5.6 (-6) mm (-7.2 mm in S. hesperium); rays usually white, sometimes pinkish-tinged (commonly purplish-blue in S. hesperium); [collectively widespread]. | |
20 Disc corolla lobes usually bright yellow (fading reddish-brown), lobes ca. 1/2 length of limb; rays mostly 16-26 (also keyed below); plants long-rhizomatous; abaxial leaf faces and midveins usually sparsely to densely strigose or strigillose | |
21 Plants short-rhizomatous and cespitose; leaf blades mostly < 1 cm wide, usually held erect-ascending; stems 1.5-6 dm tall, 1-3 mm wide at base; [rocky shores and river shoals, n. NJ northwards]. | |
21 Plants long-rhizomatous and colonial; leaf blades to 3 cm wide, lax or spreading; stems (3-) 6-15 dm tall, 3-6+ mm wide at base; [collectively widespread]. | |
24 Involucres (4-) 5-6.5 mm; rays mostly (20-) 27-36, blades 8-11 mm; disc corollas yellow (fading brownish); [TX] | |
24 Involucres (2.5-) 3.5-4.5 (-5.5) mm; rays mostly (12-)16-20, blades 5-8 mm; disc corollas cream-colored (fading purplish); [widespread]. | |
25 Heads densely crowded in spikelike racemes, the peduncles mostly < 7 mm long | |
25 Heads in loose racemes or scattered on branch ends, the peduncles mostly 10-20 mm long | |
22 Bracts foliaceous, not grading into phyllaries, 1-3 (-5) (disc corolla lobes < 1/2 length corolla limbs, erect to somewhat spreading); leaf margins flat, entire or with a few remote teeth; stem leaves sessile, slightly decurrent, often not much reduced upward (arrays leafy). | |
26 Outer phyllaries > 2/3 the length of the inner ones; heads usually subtended by large foliaceous bracts | |
26 Outer phyllaries 1/3-2/3 the length of the inner ones; heads not usually subtended by large foliaceous bracts. | |
27 Stems stout to slender, glabrous or at most hairy in lines at their bases; [collectively widespread]. | |
28 Heads congested on lateral branches of arrays; involucres 3-4 mm high; [PA, s. OH, n. KY, and AR northwards] | |
28 Heads not congested or congested only distally on lateral branches of arrays; involucres 3.6-5.6 (-6) mm high, and mostly > 4 mm high; [collectively widespread]. | |
29 Leaves linear to oblanceolate, reduced in arrays; involucres 3.6-5 (-6) mm high; rays white to purplish | |
29 Leaves broadly oblanceolate, not much reduced in arrays; involucres usually 4-5.6 mm; rays white |