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 Leaves whorled, most nodes with 3 or more leaves. | |
3 Leaves tipped by a callus (visible at 10× magnification); leaf margins entire; flowers many, grouped in a terminal involucrate head; [Eudicots] | |
4 Cauline leaves in 2-many nodes. | |
5 Leaves in 2-3 pairs, appearing verticillate; plants of marine waters; [of FL, MS, LA and southward] | |
5 Leaves along stem at 2-many nodes; plants of fresh to brackish waters; [collectively widespread]. | |
6 Flowers 3-merous; [Monocots]. | |
6 Flowers 4- or 5-merous; [Eudicots]. | |
8 Leaves 0.5-3 (-5) cm long; flowers solitary, axillary. | |
10 Leaves monomorphic, obovate, oblanceolate, or parallel-margined; corolla present (absent in Didiplis in LYTHRACEAE); stamens 2-6. | |
11 Flower radially symmetrical, 3-4-merous; petals absent or separate | |
11 Flower bilaterally symmetrical, 4-5-merous; petals present, fused at least basally, forming a tube. | |
Copy permalink to share | Check for keys that lead to this key
1 Inflorescence an involucrate head subtended by phyllaries, the heads solitary or many and variously arrayed in secondary inflorescences, the ovary inferior, the corolla connate and tubular at least basally, the calyx absent, the stamens 5, the fruit a cypsela | |
1 Inflorescence, flower, and fruit structure various, but not with the combination of features as above (sometimes the flowers in a head, e.g. Eryngium in APIACEAE, but then with other features differing, such as stamens 4, or green calyx present, or fruit a schizocarp of mericarps, etc.). | |
2 Perianth uniseriate (represented only by undifferentiated tepals or sepals) or completely absent; flowers usually unisexual, less commonly bisexual). | |
3 Inflorescence a cyathium, consisting of a single pistillate flower (reduced to a single 3-carpellate pistil) and 2 or more staminate flowers (each reduced to 1 stamen), borne in a cup-like involucre, the involucre bearing pointed or rounded glands, these sometimes brightly colored and petaloid, mimicking an individual flower (the cyathia then secondarily arranged in terminal cymes, or solitary and axillary, etc.); fresh plants with milky juice; fruit a 3-lobed, 3-locular capsule | |
3 Inflorescence not a cyathium (and staminate or bisexual flowers with > 1 stamen; fresh plants lacking milky juice (except Stillingia in EUPHORBIACEAE); fruit various, not as above. | |
7 Leaf bases cordate to rounded. | |
8 Styles 3; fruit a 3-lobed, 3-carpellate capsule (1 carpel sometimes aborting); inflorescence either a terminal or leaf opposed raceme, or a dense axillary condensed cyme with conspicuous toothed bracts subtending the flowers | |
4 Leaf margins entire. | |
11 Leaf base cuneate, rounded, or truncate; calyx of 3-4-5 distinct sepals, radially symmetrical, white or yellow; fruit a dry, nutlike drupe or an achene. | |
14 Inflorescence a leaf-opposed (sometimes apparently terminal) spike or raceme; flowers visually white from white petaloid sepals, white bracts, or white stamens. | |
15 Sepals absent; carpels 3-4; stamens 2-6 (-8); fruit a capsule, a 1-seeded drupe, or a schizocarp of 3-4 mericarps; leaf bases cordate or subcordate; [Basal Angiosperms]. | |
14 Inflorescence not leaf-opposed, either simpler (single axillary or glomerules of flowers) or more complexly branched (axillary or terminal panicles or complex cymes); flowers white, reddish, scarious, or greenish. | |
24 Petals connate. | |
25 Inflorescence various, either a terminal head, or axillary and solitary, or variously axillary or terminal and more diffuse. | |
28 Petals 4-7; stamens 1× or 2× as many as the petals, 4-7, 8, 10, 12, or14; leaves herbaceous in texture | |
30 Petals connate (at least basally), 4, 5, 6, 7, or 8; carpels 1, 2, 4, 5, or 6 (rarely 3 in Reseda in RESEDACEAE); fruit a legume or 1-, 2-, or 5-loculed capsule (except a 1-seeded indehiscent pod in Krameria in KRAMERIACEAE). | |
31 Stamens 6-10 (-25), more than the number (4 or 5) of petals and the number (4 or 5) of the sepals; fruit a legume or a 1-6-carpellate capsule. | |
35 Pistil 5-carpellate; capsule 5-locular, explosively dehiscent; inflorescence axillary, small clusters of flowers | |
35 Pistil 2-carpellate; capsule 2 locular, opening gradually or not at all; inflorescence a terminal spike, raceme or panicle (or solitary, axillary flowers in Chaenorrhinum in PLANTAGINACEAE and Krameria in KRAMERIACEAE). | |
36 Fruit 1-seeded, indehiscent; sepals petaloid, red-purple; petals dimorphic, the upper 3 long-clawed, the lower 2 small, thickened, and glandlike | |
37 Stamens 5; corolla not spurred; capsule septicidal; pubescence of the stem and leaves either gland-tipped or dendritically branched | |
37 Stamens 4; corolla with a distinct spur or sac at the base between the the 2 lower calyx lobes (except not spurred in Digitalis and Schwalbea); capsule loculicidal (only at the summit in Antirrhinum and Chaenorrhinum, and septicidal in Schwalbea); pubescence of the stem and leaves neither gland-tipped (except in Antirrhinum and Chaenorrhinum) nor dendritically branched. | |
40 Pistils 4-10 (each 1-carpellate) in a ring, these sometimes fused basally, each with its own style/stigma; fruit either an aggregate of achenes or follicles or a 5 (-7) locular capsule. | |
42 Fruit an aggregate of follicles; leaves fleshy in texture; inflorescence; leaves entire of sparsely and coarsely serrate, with < 12 points per leaf; [plants primarily of dry habitats] | |
44 Petals 5 (rarely 4 or 6); sepals 5 (rarely 4 or 6); stamens 5 (or multiples of 5), 6, or 12; fruit a capsule or a ring of mericarps. | |
47 Flowers 6-merous (the petals and sepals 6, the stamens 6 or 12); corolla pink or purplish (rarely white); fruit a septicidal capsule | |
47 Flowers 5-merous (the petals and sepals 5, stamens 5 or various multiples of 5); corolla yellow, reddish, or blue; fruit a loculicidal or septicidal capsule. | |
48 Stamens 5; corolla yellow or blue; capsule either 10-locular and septicidal or 1-locular (with 3 carpels) and loculicidal. | |
48 Stamens (5-) 10, 15, 20, 30 (-many); corolla white, pink, yellow, or reddish; capsule 3-, 5- (-10)-locular, loculicidal. | |
50 Stamens (5-) 10, 15, 20, 30 (-many); corolla yellow or reddish; capsule 3 (-10)-locular, loculicidal | |
51 Pistils 2, united only by the style and stigma; fruit a schizocarp of 2 follicles (often single by abortion); plant with milky juice when fresh; leaves entire; inflorescence an umbel | |
55 Plant an herb, erect or sprawling; leaves > 1.5 cm long. | |
61 Flowers sessile or very-short pedicelled, solitary in the leaf axils. | |
61 Flowers either solitary and obviously pedicelled, or several in an axillary or lateral inflorescence. | |
Copy permalink to share | Check for keys that lead to this key
4 Leaflets 3 (-5), sessile or subsessile, the petiolules 0-3 mm long; larger leaflets 4-8 cm long, 0.5-2.5 cm wide, averaging about 2.5× as long as wide, the apex obtuse to acute; fruit yellow-green when ripe, longitudinally winged and ribbed in ×-section; petals white (rarely tinged with pink); inflorescence nodding in bud; underground storage organ a spherical tuber | |
4 Leaflets (3-) 5, petiolulate, the petiolules (7-) 10-25 mm long; larger leaflets 6-15 cm long, 3.5-7 cm wide, averaging about 1.8× as long as wide, the apex acuminate; fruit bright red when ripe, smoothly elliptical in ×-section; petals light green; inflorescence erect in bud; underground storage organ an +/- elongate root, this vertical or horizontal, and sometimes branched | |
3 Inflorescence of single terminal flowers on the 1-several branches; fruit an aggregate of achenes; stem leaves 3 | |
1 Cauline leaves simple. | |
5 Inflorescence an involucrate head subtended by phyllaries, heads solitary or many, variously arrayed in secondary inflorescences; fruit a cypsela | |
5 Inflorescence various, but not as above; fruit various, not as above (sometimes the flowers tightly grouped, but then with other features differing, such as stamens 4, or green calyx present, or fruit a schizocarp of mericarps, etc.). | |
6 Fruit a 3-lobed, 3-locular capsule; inflorescence a cyathium, consisting of a single pistillate flower (reduced to a single 3-carpellate pistil) and 2 or more staminate flowers (each reduced to 1 stamen), borne in a cup-like involucre, the involucre bearing pointed or rounded glands, these sometimes brightly colored and petaloid, mimicking an individual flower (the cyathia then secondarily arranged in terminal cymes, or solitary and axillary, etc.); fresh plants with milky juice | |
6 Fruit various, not as above; inflorescence not a cyathium (and staminate or bisexual flowers almost always with > 1 stamen); fresh plants lacking milky juice. | |
7 Leaves herbaceous, thin in texture, whorls separated; pistil 1, of 2-5 fused carpels; fruit a capsule, achene, or drupe. | |
11 Corolla radially symmetrical, the petals separate; carpels 2, 3, or 5; stamens 5, 10, or many. | |
13 Inflorescence an axillary umbel; leaves narrowly linear and more than 10× as long as wide, > 20 mm long and < 2 mm wide; whorls of 3-6 leaves | |
13 Inflorescence a terminal cyme, raceme, panicle, or umbel; leaves as above, or broader in shape, narrower, or shorter; whorls of 3-16 leaves. | |
8 Larger whorled leaves on a plant > 10 mm wide. | |
18 Inflorescence of terminal involucrate clusters; perianth of 6 tepals; fruit an achene; stamens 9; [plants of very dry habitats] | |
21 Corolla pink-purple, 6-merous, the petals separate and borne on the edge of a hypanthium; stamens 8, 10, or 12; [plants of wetlands] | |
21 Corolla white, yellow, or greenish, 4-, 5-, or 7-merous, the petals fused at least basally into a tube (falling as a unit), not on a hypanthium; stamens 2, 4, 5, or 7; [plants of mesic habitats]. | |
22 Stamens 4, 5, or 7; corolla radially symmetrical. | |
23 Petals yellowish-white, with prominent green streaks; biennial or monocarpic plant, 10-30 dm tall when fertile; leaves 15-35 cm long | |
Copy permalink to share | Check for keys that lead to this key
1 Inflorescence an involucrate head subtended by phyllaries, the heads solitary or many and variously arrayed in secondary inflorescences, the ovary inferior, the corolla connate and tubular at least basally, the calyx absent, the stamens 5, the fruit a cypsela | |
1 Inflorescence, flower, and fruit structure various, but not with the combination of features as above (sometimes the flowers in a head, e.g. Pycnanthemum in LAMIACEAE, but then with other features differing, such as stamens 4, or green calyx present, or fruit a schizocarp of mericarps, etc.). | |
5 Leaves herbaceous, suborbicular, about as long as wide or wider than long; calyx 3- or 4-merous; stamens 4, 8, or 12. | |
5 Leaves fleshy, linear, lanceolate, to broadly ovate, at least slightly longer than broad; calyx 5-merous; stamens 3, 5, or 10. | |
4 Perianth in 2 whorls (sepals and petals both present). | |
8 Petals connate into a tube (at least basally); inflorescence often a head or dense terminal cyme (also axillary, or solitary on long peduncles). | |
14 Leaves serrate; corolla bilaterally symmetrical (especially the flowers near the outer edge of the head); inflorescence a head | |
17 Inflorescence a cyathium, consisting of a single pistillate flower (reduced to a single 3-carpellate pistil) and 2 or more staminate flowers (each reduced to 1 stamen), borne in a cup-like involucre, the involucre bearing pointed or rounded glands, these sometimes brightly colored and petaloid, mimicking an individual flower (the cyathia then secondarily arranged in terminal cymes, or solitary and axillary, etc.); fresh plants with milky juice; fruit a 3-lobed, 3-locular capsule | |
17 Inflorescence not a cyathium (and staminate or bisexual flowers with > 1 stamen, except Callitriche in PLANTAGINACEAE); fresh plants lacking milky juice; fruit various, not as above. | |
18 Flowers 1 (or 2) in leaf axils; leaves entire. | |
19 Flowers bisexual; sepals 4; flowers with 2, 4, or 6 stamens. | |
16 Perianth in 2 whorls (sepals and petals both present). | |
27 Pistils 4-5, in a single whorl; stamens 4, 5, 8, or 10; fruit an aggregate of follicles | |
28 Petals not at all connate, not even at their bases. | |
31 Petals 4-7; sepals 4-7, normally monomorphic; stamens 4, 5, 6, 8, 10, or 12 (or sometimes rarely 2 or 3). | |
28 Petals connate at least for a short distance at their bases. | |
35 Pistils 2, united only by the style and stigma; fruit a schizocarp of 2 1-carpellate follicles (often single by abortion); plant with milky juice when fresh (except Catharanthus); leaves entire | |
35 Pistil 1 (of 2-5 fused carpels); fruit either a 2-5-carpellate capsule or of 2 or 4 1-seeded nutlets derived from 2 carpels; plant lacking milky juice; leaves entire or serrate. | |
38 Inflorescence a terminal cyme; corolla salverform, with an elongated and very narrow tube, pink or white; capsule 3-locular | |
38 Inflorescence various but not cymose, of terminal or axillary racemes or panicles, or of solitary axillary flowers; corolla connate only at the base, the petals appearing nearly separate (not salverform); capsule 1-locular | |
36 Ovary and capsule 2-carpellate; fruit either a 2-locular capsule or of 2 or 4 1-seeded nutlets derived from 2 carpels. | |
40 Capsule septicidal; corolla white, pink, blue, yellowish white, or greenish white; inflorescence either a terminal or axillary cyme, or a terminal panicle or raceme, or a terminal or axillary cyme reduced to 1 or a few flowers | |
40 Capsule loculicidal and also deeply 2-lobed; corolla white, pink, or scarlet with a yellow interior; inflorescence of cymosely arranged spikes | |
42 Fruit a schizocarp of 4 1-seeded nutlets; inflorescence terminal, of cymes; corolla ca. 5 mm long; leaves prominently 3-veined | |
42 Fruit a capsule; inflorescence axillary, of cymes or clusters (often reduced to a solitary flower); corolla > 12 mm long; leaves with single primary vein | |
41 Leaves serrate; corolla salverform, the tube narrow and nearly the same diameter for most of its length; inflorescence a terminal spike, raceme, raceme of racemes, or head. | |
34 Corolla bilaterally symmetrical (or the corolla 2-lipped but the corolla lobes twisted so as to make the flower asymmetrical); fertile stamens fewer than the corolla lobes (except Plantago in PLANTAGINACEAE, which is equal, with 4 each; a few genera have a 5th, sterile, stamen which is obviously different in form than the 4 fertile stamens) (note that many corollas are bilabiate and the number of corolla lobes, 4 or 5, may be difficult to interpret); carpels 2. | |
44 Carpels 2, each carpel slightly to deeply lobed, separating at maturity into 4 half-carpellate units (not separating in Phyla in VERBENACEAE); fruit a schizocarp of 4 mericarps (or 2 nutlets in Phyla in VERBENACEAE). | |
45 Inflorescence a thyrse, verticillaster, or terminal cyme, the flowers borne in cymose lateral branches; corolla strongly bilaterally symmetrical (rarely nearly radially symmetrical); stems square in ×-section (or sometimes rounded, especially on older growth); fresh plants often (but not always) aromatic | |
45 Inflorescence of spikes, racemes, or heads, the flowers or fruits single at nodes; corolla often nearly radially symmetrical; stems rounded in X-section (rarely square); fresh plants usually not aromatic | |
47 Corolla 4-5-lobed, either strongly bilabiate or salverform (Pseuderanthemum in ACANTHACEAE); white, blue, or yellow. | |
53 Flowers in terminal racemes, panicles, or spikes, the inflorescence not interspersed with large, leaf-like bracts. | |
54 Sepals connate for at least 0.3× their length to form a tube (this cup-like and flaring in Scrophularia in SCROPHULARIACEAE). | |
55 Inflorescence a diffuse panicle; corolla 5-11 mm long, reddish-brown (sometimes with some yellow); fruit a septicidal capsule | |
55 Inflorescence of 1 or more terminal (and sometimes upper axillary) spikes or racemes; corolla 10-50 mm long (6-8 mm long in Phryma in PHRYMACEAE), white, pink, blue, purple, or yellow; fruit either a loculicidal capsule (OROBANCHACEAE) or a single seeded achene (Phryma in PHRYMACEAE). | |
56 Corolla 6-8 mm long, white to pale pink; fruit a 1-seeded achene contained in the accrescent calyx, this “lopping down” against the inflorescence axis | |
57 Sepals separate to the base or nearly so, not forming a tube. | |
59 Leaves entire, either mostly larger or smaller [see below]; plant not blackening on drying | |
60 Leaves 3-30 cm long, narrowly elliptic to lanceolate, > 2× as long as wide; plants erect or the stems sprawling; [plants mostly of uplands] | |
57 Sepals connate for at least 0.3× their length to form a tube. | |
61 Corolla yellow, orange, or red. | |
63 Corolla red or orange, with a very narrow, cylindrical tube, the lobes then flaring into a limb about 1 cm across; plants blackening on drying; [rare exotic, in crop fields, a noxious hemiparasitic weed under quarantine] | |
63 Corolla yellow, not narrowly cylindrical, the lower lip arched; plants not blackening on drying; [rare, in seepage wetlands] | |
61 Corolla white, pale blue, lavender, or pink (sometimes with some yellow). | |
64 Corolla white, blue, or combinations of blue and white (sometimes with some yellow markings); leaves broader, mostly lanceolate; plants not blackening on drying; corolla strongly bilabiate. | |
Copy permalink to share | Check for keys that lead to this key
1 Inflorescence an involucrate head subtended by phyllaries, the heads solitary or many and variously arrayed in secondary inflorescences, the ovary inferior, the corolla connate and tubular at least basally, the calyx absent, the stamens 5, the fruit a cypsela | |
1 Inflorescence, flower, and fruit structure various, but not with the combination of features as above (sometimes the flowers tightly grouped, but then with other features differing, such as stamens 4, or green calyx present, or fruit a schizocarp of mericarps, etc.). | |
2 Flowers larger, individually conspicuous; perianth present, the petals or sepals brightly colored; fruit a capsule (or aggregate of achenes in Clematis in RANUNCULACEAE or schizocarp of 4 mericarps in Glandularia in VERBENACEAE). | |
3 Flowers radially symmetrical; stamens 5 or many; fruit a capsule or aggregate of achenes. | |
3 Flowers bilaterally symmetrical (sometimes only slightly so); stamens 4 (or 2 in Veronica in PLANTAGINACEAE); fruit a capsule or schizocarp of mericarps. | |