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1 Stems below the capitulescence glabrous or nearly so, sometimes glaucous. |
..2 Leaves whorled at principal nodes, either alternate or opposite at other nodes |
..2 Leaves either alternate or opposite (or both), never whorled. |
....3 Leaves grayish-green or bluish green in color, sessile, and glabrous and glaucous on the undersurface. |
......4 Rays 10-14; leaves strumose adaxially, rough to the touch; phyllaries 3.5-4.5 mm wide |
......4 Rays 5-10; leaves glabrous or glabrate adaxially, smooth or only slightly rough to the touch; phyllaries 2-3 mm wide |
....3 Leaves light to dark green, sometimes whitish abaxially, but not grayish or bluish green in color; leaves sessile or petiolate, glabrous or pubescent. |
........5 Leaves linear-lanceolate, with only a single main vein |
........5 Leaves linear-lanceolate to lanceolate, lance-ovate, or ovate, triplinerved at base. |
..........6 Rays few, usually 5 or 8; heads small, the involucres 9 mm broad or less. |
............ 7 Leaves abaxially whitish in color and glabrous and glaucous, lacking subsessile glandular trichomes (‘resin dots’) |
............ 7 Leaves abaxially greenish in color, usually tomentulose (sometimes glabrate), with abundant subsessile glandular trichomes |
..........6 Rays usually 10 or more in larger heads; heads larger, the involucres usually > 9 mm broad. |
............ ..8 Leaves sessile, rounded to cordate at base, and trinerved, with the 2 lateral veins diverging from the midrib at the very base of the leaf |
............ ..8 Leaves sessile to petiolate, but narrowing gradually to base and triplinerved, the 2 lateral veins diverging from the midrib above the base of the blade. |
............ ....9 Anther appendages yellow. |
............ ......10 Leave blade lanceolate to lance-ovate, sessile to petiolate but the petiole usually < ¼ as long as the blade; phyllaries not conspicuously graduated and imbricate, usually loose and spreading |
............ ......10 Leaf blade ovate to elliptic, with a distinct petiole usually > 2 cm long and ½ as long as blade or longer; phyllaries conspicuously graduated and imbricate, usually appressed, not exceeding disk |
............ ....9 Anther appendages dark or reddish-brown. |
............ ........11 Plants producing abundant tubers; leaves subsessile, the petioles < 1 cm long; [endemic to the Piedmont of NC and SC] |
............ ........11 Plants rhizomatous, but not producing tubers; leaves petiolate, the petioles 1-5 cm long; [collectively widespread in our area]. |
............ ..........12 Longer phyllaries usually exceeding disk by ½ their length or more, apex acuminate; larger leaves moderately to conspicuously serrate, with a petiole 2-5 cm long, and abaxially with usually relatively few subsessile glandular trichomes |
............ ..........12 Phyllaries equal to or slightly exceeding disk, apex acute; leaves moderately serrate to entire, with a petiole 1-3 cm long, and abaxially with usually abundant subsessile glandular trichomes (‘resin dots’) |
1 Stems pubescent throughout, not glaucous. |
............ ............ 13 Leaves sessile and cordate, mostly or all opposite |
............ ............ 13 Leaves petiolate or sessile, but not cordate, and alternate or opposite. |
............ ............ ..14 Phyllaries attenuate, conspicuously exceeding the disk in length and reflexed, apically with numerous subsessile glandular trichomes (‘resin dots’); leaf bases often convex, the basically ovate or lance-ovate blade joined to a broadly winged and gradually narrowed petiole |
............ ............ ..14 Phyllaries acute to attenuate, but not reflexed, subsessile glandular trichomes present or absent; leaf bases usually attenuate to truncate or rounded, the blade lance-linear or lanceolate, or if ovate or lance-ovate either sessile or with a petiole that is at most narrowly winged. |
............ ............ ....15 Leaves conduplicate (strongly folded along the midvein, thus V-shaped) and entire, usually with only a single prominent main vein; inflorescence when well developed spiciform or racemose |
............ ............ ....15 Leaves not conduplicate, entire or serrate, triplinerved (with a prominent lateral pair of veins near the base); inflorescence not spiciform or racemose. |
............ ............ ......16 Phyllaries conspicuously graduated and imbricate, usually appressed. |
............ ............ ........17 Leaf blades lanceolate to ovate, petiole 1-5 cm long and usually < ½ as long as blade; anther appendages with dark pigment; cypselas 4-5 mm, usually sterile |
............ ............ ........17 Leaf blades ovate to elliptic, petiole distinct, > 2 cm and usually > ½ as long as the blade; anther appendages yellow; cypselas 3-4 mm long, fertile |
............ ............ ..........18 Leaves rough to touch, scabrous or hirsute; leaves entire or nearly so; [widely distributed] |
............ ............ ..........18 Leaves smooth to touch, strigose or glabrous; leaves usually serrate; [w. LA, AR, TX] |
............ ............ ......16 Phyllaries not conspicuously graduated and imbricate, usually loose or spreading. |
............ ............ ............ 19 Leaves with a prominent petiole > 2 cm long, blades lance-ovate to ovate and > 5 cm broad; cypselas 5-7 mm long; tubers produced late in growing season |
............ ............ ............ 19 Leaves sessile or with a short petiole usually < 2 cm long; blades linear to lanceolate, < 4.5 cm broad; cypselas 3-5 cm long; tubers present or absent. |
............ ............ ............ ..20 Leaves truncate to broadly rounded at base, shortly but distinctly petiolate |
............ ............ ............ ..20 Leaves cuneate, gradually narrowing to base, sessile to petiolate. |
............ ............ ............ ....21 Ligules lacking subsessile glandular trichomes; leaves not strongly revolute |
............ ............ ............ ....21 Ligules abaxially with subsessile glandular trichomes (‘resin dots’); leaves usually revolute. |
............ ............ ............ ......22 Heads relatively small, the discs usually < 15 mm across; tubers present |
............ ............ ............ ......22 Heads larger, the discs (at least the larger) > 15 mm across; tubers absent. |
............ ............ ............ ........23 Leaves conspicuously undulate; ovate to elliptical to lanceolate, occasionally linear (if so, usually < 10 cm long), usually < 5× as long as wide; heads 1-6 per plant; outer phyllaries acute to obtuse |
............ ............ ............ ........23 Leaves not conspicuously undulate; linear to lanceolate, > 5× as long as broad (and also 8-16 cm long); heads 3-16 per plant; outer phyllaries acuminate to acute. |
............ ............ ............ ..........24 Plants short, < 1.5 m tall; leaves < 1 cm wide; rhizomes lacking or poorly developed |
............ ............ ............ ..........24 Plants robust, > 1.5 m tall; leaves > 1 cm wide; rhizomes well developed |