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 Head 1 per plant (individual rosette); stems 0.1-0.3 dm tall; [TX and OK westwards] | |
2 Stems with numerous thorns (1-2 cm long, modified axillary branches), and few or no leaves | |
2 Stems leafy, not armed with thorns. | |
4 Annuals from taproots; ray florets 0.3-7 mm long. | |
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 | |
10 Heads borne either in flat-topped or rounded, corymbose arrays, or in narrow racemiform or spiciform panicles, or solitary. | |
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] | |
13 Heads borne either in flat-topped or rounded, corymbose arrays, or in narrow racemiform/spiciform panicles, or solitary. | |
15 Heads borne in corymbose arrays. | |
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. | |
Copy permalink to share | Check for keys that lead to this key
1 Receptacles paleate (with chaff); [tribe Heliantheae]. | |
2 Stems usually winged; leaves simple or pinnately to palmately lobed; disc florets concolorous (of similar color) with ray florets | |
1 Receptacles epaleate (lacking chaff). | |
5 Receptacles flat or broadly conic, not conspicuously pitted; heads in corymbiform arrays; pappus a short crown; rays white, pink, or purple adaxially; [widespread non-natives, tribe Anthemideae] | |
5 Receptacles conic, pitted; heads borne singly (Aphanostephus) or in loose corymbiform arrays (Egletes); rays white adaxially; [natives primarily w. of MS river; tribe Astereae]. | |
7 Plants 1-3 cm tall, densely pin-cushioned (pulvinate); flowering heads sessile, borne singly, conspicuously nestled within the rosette leaves and proportionately of similar size; pappus persistent, of 12-35+ setiform scales in 1 series; phyllaries in 4-6+ series | |
7 Plants of various size, but not densely pin-cushioned; flowering heads borne on stems, if peduncles short the heads not conspicuously nestled within similar-sized leaf rosettes; pappus various, phyllaries in 2-6 series. | |
9 Inner barbellate bristles numerous (5-40+); stems and leaves usually glandular; plants tap-rooted, fibrous-rooted, or stoloniferous; annuals, biennials, or perennials | |
9 Inner bristles barbellate or thicker, fewer (ca. 5); stems and leaves glandular (C. asteroides) or eglandular (C. asteroides; C. belliloides); plants tap-rooted annuals | |
8 Pappus primarily of awns, scales, crowns, or thickened rings (these minute, 0.1-0.8 mm long), sometimes also accompanied by shorter inner scales or bristles; stems and leaves eglandular (sometimes minutely glandular in Chaetopappa bellidifolia). | |