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1 Leaves linear, lanceolate, or oblancolate, > 4× as long as wide. |
..2 Leaves phyllodial (septate, hollow or flat, segmented); flowers white or purple; [plants of wetlands]. |
....3 Umbels simple; leaves spatulate, broader towards the tip, often somewhat flattened in ×-section, rounded or obtuse at the apex |
....3 Umbels compound; leaves tapering to a pointed tip, either flat or terete in ×-section. |
......4 Leaves flat in ×-section, with obvious parallel venation and less obvious septae / cross-partitions |
......4 Leaves terete in ×-section, the septae obvious. |
........5 Plants 1-11 dm tall, annuals, sometimes mat-forming and adventitiously perennial; fruits 1-3 mm long, with lateral ribs; rays 3-15 |
........5 Plants 6-24 dm tall, perennials from rhizomes or tubers; fruits 4-9 mm long, with lateral wings; rays 5-20 |
..2 Leaves “normal” (non-septate, flat, continuous, and in some cases lobed, toothed, or spinose-margined); flowers blue, yellow, white, or whitish-green; [plants of wetlands or uplands]. |
..........6 Flowers borne in involucrate heads; corolla blue or greenish-white |
..........6 Flowers in compound umbels; corolla yellow or white. |
............ 7 Stem leaves similar to the basal, all simple; corollas yellow; [exotic, of disturbed areas] |
............ 7 Stem leaves palmately 3-5-foliolate with linear leaflets, differing from the simple basal leaves; corollas white; [native, of blackland prairies and associated disturbed areas, from AL and TN westward] |
1 Leaves orbicular, ovate, or elliptic, < 4× as long as wide. |
............ ..8 Leaves orbicular, about as wide as, or wider than, long; base peltate or cordate. |
............ ....9 Leaves leathery, with spinose margins; inflorescence a head; flowers blue; [rare introduction] |
............ ....9 Leaves herbaceous or somewhat fleshy. toothed or lobed, but not spinose; inflorescence umbellate or verticillate; flowers white, greenish, or purplish; [collectively common and widespread]. |
............ ......10 Foliage and fruits (or ovaries) stellate-pubescent or glochidiate; leaves lobed, but otherwise entire; [rare exotic] |
............ ......10 Foliage and fruits (or ovaries) glabrous; leaves toothed, sometimes also lobed; [common natives and exotics] |
............ ..8 Leaves ovate or elliptic, 1.2-4× as wide as long; base cordate, peltate, or truncate. |
............ ........11 Leaves perfoliate; flowers yellow; [rare exotics]. |
............ ..........12 Stem leaves entire; umbellets subtended by broad foliaceous bractlets |
............ ..........12 Stem leaves serrate; umbellets lacking bractlets |
............ ........11 Leaves cordate or truncate at the base; flowers white, green, yellow, blue, or purple; |
............ ............ 13 Flowers greenish or blue; leaves all simple (sometimes stem leaves lobed); inflorescence a head or very congested (subcapitate) umbel; [plants of wetland situations, prostrate, creeping, or erect]. |
............ ............ ..14 Inflorescence a very congested (subcapitate) umbel, with 4-9 flowers; leaves cordate at the base, long-petiolate, the petioles characteristically 2× as long as the leaf |
............ ............ ..14 Inflorescence a head, with > 20 flowers; leaves cuneate to truncate at the base, sessile to short petiolate, the petioles < 1× as long as the leaf (except E. prostratum) |
............ ............ 13 Flowers yellow or purple; basal leaves simple, stem leaves usually compound; Inflorescence a compound umbel; [erect plants of upland situations]. |
............ ............ ....15 Fruits (partly to fully mature) with thin-edged wings; flowers yellow or purple; central flower of each umbellet staminate and pedicelled; fruits all pedicelled in all umbellets |
............ ............ ....15 Fruits ribbed (with rounded, cordlike ribs), lacking thin-edged wings; flowers yellow; central flower of each umbellet either staminate and pedicelled, or pistillate and sessile; fruits all pedicelled in some umbellets (those with a staminate central flower), or the central fruit sessile in some umbellets (those with a pistillate central flower) |
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..2 Leaflets linear (resembling winged rachises); corolla white |
..2 Leaflets broad, elliptic, ovate, or obovate, sparingly lobed; corolla yellow |
1 Leaflets variously serrate, dentate, and/or incised. |
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......4 Corolla yellow, maroon, or pale creamy yellow. |
........5 Flowers yellow, maroon, or pale creamy-yellow; central flower of each umbellet staminate and pedicelled; fruits all pedicelled in all umbellets; developing fruits subterete to slightly dorsally compressed, several or all of the ribs with thin-edged wings |
........5 Flowers yellow; central flower of each umbellet either staminate and pedicelled, or pistillate and sessile; fruits all pedicelled in some umbellets (those with a staminate central flower), or the central fruit sessile in some umbellets (those with a pistillate central flower); developing fruits laterally compressed, all of the ribs rounded and cordlike |
......4 Corolla white. {Add to keylead 4b: Apium graveolens var. dulce, Cicuta bolanderi, Cicuta mexicana, Imperatoria ostruthium, Petroselinum crispum} |
..........6 Ovary hispid or pubescent. |
............ 7 Rays 16-25; leaves somewhat coriaceous; leaflet bases often cuneate or obliquely truncate; [plants of dry habitats] |
............ 7 Rays 3-5; leaves thin in texture; leaflet bases rounded, subcordate, or broadly cuneate; [plants of moist forests] |
..........6 Ovary glabrous. |
............ ..8 Plants 1-9 dm tall at maturity; [rarely naturalized exotics]. |
............ ....9 Ovary (and later the fruits) terete, the ribs corky-winged; [plants of wetlands] |
............ ....9 Ovary (and later the fruits) laterally compressed, not winged; [plants of uplands] |
............ ......10 Umbellets (rays) 9-15 per umbel |
............ ......10 Umbellets (rays) (25-) 50-100 per umbel |
............ ..8 Plants 6-18 dm tall at maturity; [collectively common and widespread natives]. |
............ ........11 Sheaths of the upper leaves dilated, > 1 cm wide when flattened; [plants of moist habitats, from GA northward in the Mountains, extending into adjacent provinces towards the northern edge of our area] |
............ ........11 Sheaths of the upper leaves not dilated, < 1 cm wide; [plants either of wetlands or of moist to dry forests]. |
............ ..........12 Veins of the leaflets directed to the sinuses; leaflets mostly 2.5-5× as long as wide, acuminate at the tip; [of wetlands] |
............ ..........12 Veins of the leaflets directed to the tips of the teeth or lobes; leaflets mostly 1.3-1.8× as long as wide, acute to obtuse at the tip; [of moist to dry forests] |
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............ ............ 13 Fruit hispid or pubescent (regardless of winging). |
............ ............ ..14 Fruits 4-6 mm long, hispid across the surfaces; rays 16-25; leaves somewhat coriaceous; leaflet bases often cuneate or obliquely truncate; [plants of dry habitats] |
............ ............ ..14 Fruits 18-24 mm long, oblanceolate or linear, appressed-pubescent on the ribs; rays 3-5; leaves thin in texture; leaflet bases rounded, subcordate, or broadly cuneate; [plants of moist forests] |
............ ............ 13 Fruit glabrous (sometimes winged or prominently ribbed as well). |
............ ............ ....15 Fruits dorsally compressed (strongly to slightly) or subterete, either thin-winged or corky-winged. |
............ ............ ......16 Ribs very corky; fruits 2-3 mm long; [rare aquatic or semiaquatic exotic] |
............ ............ ......16 Ribs thin-winged; fruits 3-8 mm long; [common natives of most to submesic forests]. |
............ ............ ........17 Rays 12-30; fruits 4-8 mm long; plant 6-20 dm tall; sheaths of the upper leaves dilated, > 1 cm wide when flattened |
............ ............ ........17 Rays 5-10; fruits 3-6 mm long; plant 5-10 dm tall; sheaths of the upper leaves not dilated, < 1 cm wide |
............ ............ ....15 Fruits laterally compressed, not winged (except thin-winged in Ligusticum). |
............ ............ ..........18 Veins of the leaflets directed to the sinuses; leaflets mostly 2.5-5× as long as wide, acuminate at the tip; [of wetlands] |
............ ............ ..........18 Veins of the leaflets either directed to the tips of the teeth or lobes, or reticulating extensively and becoming obscure before reaching the margin; leaflets mostly 1.3-1.8× as long as wide, acute to obtuse at the tip; [of moist to dry forests]. |
............ ............ ............ 19 Leaflet venation palmate-ternate, each leaflet with 3 (-5) main veins from the base (the central vein then with pinnate secondary veins); plants from rhizomes |
............ ............ ............ 19 Leaflet venation pinnate, each leaflet with a dominant central vein (it then with pinnate secondary veins); plants from a caudex, taproot, or cluster of fibrous or fleshy roots. |
............ ............ ............ ..20 Lateral veins of the leaflet parallel and straight, clearly extending to the tip of each tooth; leaflet base often strongly oblique; leaflet margin entire in the lower ¼ to 1/3 |
............ ............ ............ ..20 Lateral veins of the leaflet arcing, reticulating and becoming obscure before reaching the leaflet margin; leaflet base symmetrical or slightly oblique; leaflet margin toothed to or very close to the base |
............ ............ ............ ....21 Umbellets (rays) per umbel (25-) 50-100 |
............ ............ ............ ....21 Umbellets (rays) per umbel 4-25 |