Colors

Data mode

Account

Login
Sign up

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.

Key to Asteraceae, Key C: herbaceous composites with opposite leaves and radiate heads

Copy permalink to share | Check for keys that lead to this key

1 Involucre of phyllaries subtended by a calyculus of bracts obviously different in color, texture, and shape than the phyllaries; [tribe Heliantheae; subtribe Coreopsidinae].
..2 Phyllaries connate for at least ¼ their length; [MS westwards in our area]
..2 Phyllaries distinct; [collectively widespread in our area].
....3 Cypselas beaked, not strongly flattened, 7-30 mm long, with 1 groove per face; leaves highly dissected
....3 Cypselas beakless, more or less strongly flattened and also often winged, 1.2-16 mm long, with 0 or 2 grooves per face; leaves simple to highly dissected.
......4 Cypselas 2.5-16 mm long, usually not winged; pappus awns (if present) usually retrorsely barbed
......4 Cypselas 1.2-8 mm long, usually winged; pappus awns (if present) barbless or antrorsely barbed
1 Involucre of phyllaries not subtended by a calyculus (or subtended by a calyculus of narrowly linear segments bearing oil glands in Dyssodia and Thymophylla).
........5 Ray florets white, pink, or purple (rarely pale yellow or lavender).
..........6 Ray flower persistent on the achene and becoming papery and bleached.
..........6 Ray flower articulate from the achene and falling.
............ 7 Pappus of a minute crown; disk florets white or whitish
............ 7 Pappus either lacking, or of numerous scales, or of retrorsely barbed awns; disk florets yellow.
............ ..8 Annual of disturbed habitats; leaves usually < 1 dm long; phyllaries < 5 mm long
............ ..8 Perennial of native habitats; leaves > 1 dm long; phyllaries > 6 mm long
........5 Rays predominantly yellow, orange, or red (sometimes with some brown, maroon, or purple coloration as well).
............ ....9 Receptacle naked, epaleate.
............ ......10 Leaves and phyllaries with large, scattered, embedded oil glands, translucent in living plants, usually golden-brown or blackish in herbarium specimens), making the plants strongly aromatic; annual plants, decumbent and much branched from the base (except Tagetes, annual and generally erect and sparingly branched); [tribe Heliantheae; subtribe Pectidinae].
............ ........11 Leaves unlobed, entire (though with marginal setae)
............ ........11 Leaves pinnately lobed, the margins also often serrate.
............ ..........12 Pinnate leaf segments lanceolate, 3-10 mm wide; calyculus absent
............ ..........12 Pinnate leaf segments linear, 1-3 mm wide; calyculus present, subtending the involucre, of linear bracts.
............ ............ 13 Phyllaries distinct to their bases, or nearly so
............ ............ 13 Phyllaries connate > ½ their length
............ ......10 Leaves and phyllaries lacking embedded oil glands, though smaller punctate glands sometimes present; perennial or annual plants, upright and little or moderately branched below the inflorescence.
............ ............ ..14 Phyllaries 6 (-9), in 1 series; disc florets 1-15
............ ............ ..14 Phyllaries 12-26, in 2-3 series; disc florets 20-150.
............ ............ ....15 Pappus of 5-6 aristate scales; [exotic, rare waif in our area]
............ ............ ....15 Pappus of barbellate bristles (or absent); [native, collectively fairly widespread in our area].
image of plant
Show caption*© Scott Ward
............ ............ ......16 Phyllaries 12-18; rays usually 8-16; leaves mainly basal or basally disposed (a few pairs low on the stem); [on various, usually acid substrates, in the Coastal Plain and Piedmont from NJ and PA south to n. and Panhandle FL]
image of plant
Show caption*© Scott Ward
............ ............ ......16 Phyllaries broadly ovate, squarrose, in several imbricate series; rays usually 8; leaves cauline; [on calcareous substrates in n. AL]
............ ....9 Receptacle paleate, with paleae, bristles, or scales.
image of plant
Show caption*© Scott Ward
............ ............ ........17 Disk florets functionally staminate (“sterile”, not producing cypselas), the style undivided, their ovaries much smaller than those of the ray flowers (which are functionally pistillate).
image of plant
Show caption*© Swarochi Tathagath, some rights reserved (CC BY), uploaded by Swarochi Tathagath
............ ............ ..........18 Inner phyllaries prickly with straight or uncinate prickles, and each enveloping a cypsela and swelling into a bur-like structure
............ ............ ..........18 Inner phyllaries unarmed, not becoming bur-like (though those of Melampodium do invest the fruit).
............ ............ ............ 19 Outer phyllaries orbicular, connate 1/4 - 1/3 of their lengths; [alien, rare]
............ ............ ............ 19 Outer phyllaries orbicular to narrower, not connate; [native, collectively widespread in our area].
image of plant
Show caption*© Gary P. Fleming
............ ............ ............ ..20 Slender, small plants, the stems to 5 dm long, often trailing; pappus persistent, forming a crown
image of plant
Show caption*© Alan M. Cressler
............ ............ ............ ..20 Taller, robust plants, the stems usually 5-40 cm long at maturity, erect; pappus absent or of 2 awns.
image of plant
Show caption*© Scott Ward
............ ............ ............ ....21 Cypselas strongly flattened, borne in 2-3 series from the 2-3 series of ray florets
image of plant
Show caption*© Scott Ward
............ ............ ............ ....21 Cypselas thick, not flattened, borne in 1 series from the 1 series of ray florets
............ ............ ........17 Disk florets functionally bisexual (“fertile”, producing cypselas), the style divided, their ovaries as large as, or larger than, those of the ray florets (which may be either functionally pistillate or completely neuter).
............ ............ ............ ......22 Ray corolla persistent on the achene and becoming papery and bleached.
............ ............ ............ ........23 Plant a perennial; cypselas subterete, 4-5 mm long
............ ............ ............ ........23 Plant an annual; cypselas 3-angled or flattened, 6-10 mm long
............ ............ ............ ......22 Ray corolla articulate from the achene and falling after flowering.
............ ............ ............ ..........24 Pappus of 20 plumose bristles 4-5 (-7.5) mm long
............ ............ ............ ..........24 Pappus various, but not as above.
............ ............ ............ ............ 25 Paleae flattened, not notably clasping the cypsela; cypsela usually notably flattened in the same plane as the phyllaries and the paleae, i.e. at a right angle to the radii of the head; heads small, the receptacle 3-8 mm in diameter.
............ ............ ............ ............ ..26 Cypselas dimorphic, those of the ray florets with lacerate wings
............ ............ ............ ............ 25 Paleae conduplicate (V-shaped in cross section), the 2 sides of the V partially clasping the cypsela; cypsela either subterete, multi-angled in ×-section, or flattened parallel to the radii of the head; heads mostly larger.
............ ............ ............ ............ ....27 Phyllaries apparently 4 (the 4 outer foliaceous phyllaries forming a quadrangle which hides the much smaller and narrower inner phyllaries)
............ ............ ............ ............ ....27 Phyllaries not as above (5 or more phyllaries readily visible).
............ ............ ............ ............ ......28 Cypselas (of at least the disk florets) strongly flattened and generally also winged.
............ ............ ............ ............ ........29 Cypselas 1-2.5 mm long; herb to 2 dm tall (erect or creeping)
............ ............ ............ ............ ........29 Cypselas 3-7 mm long; herb to 1-40 dm tall (erect)
............ ............ ............ ............ ......28 Cypselas subterete, quadrangular, variously angled, or diamond-shaped in ×-section, not winged.
............ ............ ............ ............ ............ 31 Erect herb; leaves entire or with a few teeth; peduncles < 3 cm long
............ ............ ............ ............ ............ 31 Creeping herb; leaves serrate and also mostly 3-lobed; peduncles 3-10 cm long
............ ............ ............ ............ ............ ..32 Leaves linear, lanceolate, or ovate, almost always some leaves on a plant > 7 mm wide; plants from crowns, some species with thickened vertical storage roots (only H. tuberosus producing horizontal tubers); [collectively widespread in our area]
............ ............ ............ ............ ............ ..32 Leaves linear, 0.5-7 mm wide; plants from slender horizontal tubers; [of Coastal Plain of FL and s. AL]
Cite as...