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1 Basal and lower stem leaves petiolate, with blades cordate to rounded at the base; [subg. Symphyotrichum, sect. Symphyotrichum, subsect. Heterophylli] |
1 Basal and lower stem leaves sessile (often cordate-clasping), or if petiolate then with cuneate to attenuate bases. |
..2 Vegetative parts (stems, leaves, array branches, phyllaries) persistently bluish-glaucous; leaves slightly fleshy in texture and clasping; plants nearly glabrous (leaf margins scabrous, rarely upper stems somewhat hirsute); stems 2-7 (-12) dm tall; [subgenus Symphyotrichum, section Symphyotrichum, subsection Heterophylli, series Concinni]. |
..2 Vegetative parts (stems, leaves, array branches, phyllaries) green, not bluish-glaucous; leaves mostly not fleshy (except subg. Astropolium); plants glabrous or variously hairy; stems 2-30 dm tall. |
....3 Leaves strongly basally disposed, basal leaves linear, upper cauline leaves much reduced; heads few, long-pedunculate (peduncles 1-20+ cm) in open ± corymbiform arrays; disc florets 47-57; [of wet pine savannahs of FL and s. AL]; [subgenus Chapmaniani]. |
....3 Leaves cauline, basal and proximal leaves generally not linear, often withered by anthesis; heads few to many, mostly in paniculiform or racemiform arrays; disc florets often fewer; [collectively widespread]. |
......4 Ray florets mostly in 2-3 series, blades 1.3-4.2 mm, often not exceeding mature pappus ( S. tenuifolium and S. bracei in 1 series to 8.5 mm); plants appearing entirely glabrous (leaf axils or margins sometimes inconspicuously strigillose); plants either taprooted annuals or perennials with succulent, linear, entire leaves; [coastal wetlands, often saline, or disturbed areas inland]; [subgenus Astropolium] |
........5 Leaves succulent, linear (1-6 mm wide) and entire; ray laminae (4.5-) 5-8.5 (-9) mm, in a single series; plants perennial, heads (1-) 3-20 (-40). |
........5 Leaves not succulent, usually broader or toothed; ray laminae 1.3-4.2 mm, usually in 2-3 series (laminae 3.7-7 mm and in 1 series in S. divaricatum); plants annual, often copiously branched, heads (10-) 30-100 (-150+). |
......4 Ray florets in 1 series, mostly >4mm; stems usually pubescent at least in lines distally, leaves often pubescent or scabrous; plants perennials from crowns, caudices, or rhizomes, leaves not succulent; [various habitats, rarely saline]. |
..........6 Stem leaves sessile, entire, and cordate- or auriculate-clasping at base (if only rounded or cuneate, then mostly 1-3 cm long); leaves crowded, internodes of main stem < 3.5 cm long (rarely longer in S. patens); plants stipitate-glandular in arrays (on upper stems, leaves, peduncles, bracts, and/or phyllaries; absent in sect. Concolores and sparse to absent in some vars. of S. patens); rays purple, blue, or lavender; [subgenus Virgulus] |
..........6 Stem leaves winged-petiolate (lower, often withering by anthesis) to sessile (upper), often toothed, bases attenuate to auriculate-clasping (main stem leaves mostly > 3 cm long); leaves not crowded, internodes of main stem > 3.5 cm long; arrays eglandular; rays white in some species. |
............ 7 Phyllary tips widely spreading or recurved, usually either involute or foliaceous, faces glabrous or variously pubescent. |
............ ..8 Phyllary apices spinose, either tightly involute or tipped with a white spine; flowers white (except S. kentuckiense). |
............ ....9 Free tips of phyllaries flat, tipped with a white spine (otherwise acute); stem leaves crowded (internodes mostly <1 cm), linear or oblong, 1-4 mm wide, usually upcurved; [subgenus Virgulus, section Ericoidei] |
............ ....9 Free tips of phyllaries tightly involute, long-acuminate; stem leaves not crowded, often broader, not upcurved; [subgenus Symphyotrichum] |
............ ..8 Phyllary tips acute to acuminate, flat; flowers pink, purple, or lavender (rarely white in S. firmum). |
............ ......10 Upper stems, peduncles, bracts, and phyllaries ±densely hirtellous and usually also stipitate-glandular; leaves entire, sessile, and mostly rounded to subclasping at base; [subgenus Virgulus] |
............ ......10 Stems pubescent in lines distally (densely hirsute in S. puniceum), plants eglandular; leaves usually toothed, lower winged-petiolate, upper auriculate-clasping or cuneate; [subgenus Symphyotrichum] |
............ 7 Phyllary tips appressed to ascending, faces glabrous (rarely sparsely strigillose). |
............ ........11 Involucres turbinate, phyllaries in 6-9 series; ray laminae 12-20 mm long, pink to purple; peduncles (1-) 4-10 (-25) cm with numerous (8-15) appressed, linear-oblong bracts 1.5-4mm; stem leaves lacking axillary clusters; [subgenus Symphyotrichum, section Turbinellum] |
............ ........11 Involucres campanulate to cylindric, phyllaries in 3-6 series; ray laminae 3-11 (-14) mm long (longer in S. boreale); peduncles not as above (except S. dumosum and S. estesii); stem leaves with or without axillary clusters |
1 Head 1 per plant (individual rosette); stems 0.1-0.3 dm tall; [TX and OK westwards] |
1 Heads 5-300+ per (well-developed) plant; stems 0.3-35 dm tall; [collectively widespread]. |
..2 Stems with numerous thorns (1-2 cm long, modified axillary branches), and few or no leaves |
..2 Stems leafy, not armed with thorns. |
....3 Leaves pinnatifid to bipinnatifid; plant annual |
....3 Leaves unlobed; plant perennial from caudices, crowns, or rhizomes. |
......4 Annuals from taproots; ray florets 0.3-7 mm long. |
........5 Ray laminae 0.3-1.0 mm long; cypselas 1.0-1.5 mm long, compressed, 1-nerved on each face |
........5 Ray laminae 1.3-7 mm long; cypselas (1.2-) 1.5-2.7 (-3) mm long, compressed or not, 5-18-nerved. |
..........6 Disc flowers 25-35 per head; ray flowers in 1 series |
..........6 Disc flowers 4-10 (-13) per head; ray flowers in 1-3 series |
......4 Perennials from caudices, crowns, or rhizomes; ray florets > 3 mm long. |
............ 7 Basal and lower stem leaves petiolate, with blades cordate to rounded at the base |
............ ..8 Heads borne in corymbiform arrays, the branches often subtended by large and leaf-like bracts; phyllaries < 2.5 (-3)× as long as wide, often > 1 mm wide; plants (in most species) colonial by rhizomes; rays (in most species) white; phyllaries (in many species) glandular |
............ ..8 Heads borne in paniculiform arrays, the branches bearing small and narrow bracts; phyllaries > 3× as long as wide, often < 1 mm wide; plants (in most species) solitary; rays (in most species) blue, violet, or pink; phyllaries eglandular |
............ 7 Basal and lower stem leaves sessile (sometimes cordate-clasping), or if petiolate then with cuneate to attenuate bases. |
............ ....9 Rays pink, purple, lavender, blue, or pale pink [plants with pale pink rays may need to be keyed both ways]. |
............ ......10 Heads borne in paniculiform or in diffuse and irregular arrays |
............ ......10 Heads borne either in flat-topped or rounded, corymbose arrays, or in narrow racemiform or spiciform panicles, or solitary. |
............ ........11 Leaves 1.2-4.0 cm long, 1-4 mm wide, stiff, scabrous margined and weakly spine-tipped; plants 1-7 dm tall; pappus in 2 series, the inner much longer than the outer (ca. 1 mm long) bristles |
............ ........11 Leaves either longer or broader or both, herbaceous; Leaves (5-) 13-45 mm wide, herbaceous, neither scabrous-margined nor spine-tipped; plants 4-30 dm tall; pappus not divided into distinct inner and outer series. |
............ ..........12 Plants 10-35 dm tall; larger leaves (basal or low on the stem) with cuneate or attenuate bases, the blades 30-50 cm long; [non-native, rarely persistent or spreading from horticultural use] |
............ ..........12 Plants 1-12 dm tall; larger leaves with blades 2-20 cm long; [natives, collectively widespread and common in our region] |
............ ....9 Rays white (or very slightly pink-flushed). |
............ ............ 13 Heads borne in paniculiform or in diffuse and irregular arrays |
............ ............ 13 Heads borne either in flat-topped or rounded, corymbose arrays, or in narrow racemiform/spiciform panicles, or solitary. |
............ ............ ..14 Heads arrayed in 1 (or more) cylindrical thyrses |
............ ............ ..14 Heads borne in either narrow racemiform/spiciform panicles, or in corymbose arrays. |
............ ............ ....15 Heads borne in narrow racemiform/spiciform panicles |
............ ............ ....15 Heads borne in corymbose arrays. |
............ ............ ......16 Disc flowers white |
............ ............ ......16 Disc flowers yellow (and often fading to pink or purplish). |
............ ............ ........17 Rays 2-7, the ray ligules 2-11 mm long, often twisted or contorted; phyllaries whitish with a distinct green tip, the green area about as wide as long |
............ ............ ........17 Rays (8-) 9-40, the ray ligules 4-20 mm long, generally planar (or neatly coiling at post-maturity); phyllaries various. |
............ ............ ..........18 Pappus double, with an outer set of bristles < 1 mm long; leaves entire |
............ ............ ..........18 Pappus not divided into distinctively different outer and inner series; leaves toothed or entire. |
............ ............ ............ 19 Achenes not glandular, either glabrous or strigillose |
............ ............ ............ 19 Achenes densely gland-dotted |