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1 Capsule turgid, longer than wide; leaves monomorphic; [collectively of many habitats and widespread]. | |
2 Flowers and fruits sessile or subsessile, the pedicels < 1 mm long; perennial. | |
5 Calyx subtended by 0 (-1) bractlet; corolla lobes white; corolla tube greenish yellow, conspicuously veined | |
5 Calyx subtended by 2 bractlets; corolla lobes white or yellow-orange; corolla tube greenish yellow and conspicuously veined, or orange and not conspicuously veined. | |
6 Corolla lobes and tube yellow-orange (very rarely white), not conspicuously veined; sepals and flower stalks sparsely or not at all glandular-puberulent | |
6 Corolla lobes white to lavender, corolla tube greenish yellow, usually conspicuously veined; sepals and flower stalks densely glandular-puberulent. | |
7 Leaves oblong-ovate to ovate (or linear-lanceolate in submersed forms), finely dentate; corolla veined with purple lines; sepals lanceolate to oblong-lanceolate | |
7 Leaves triangular to lanceolate, margins entire, or with a few teeth toward the tip; corolla veined with brown lines; sepals linear-lanceolate | |
8 Leaves 3.5× as long as wide; lower leaf surface with only sunken, translucent glands | |
8 Leaves < 3× as long as wide; lower leaf surface with large, yellow sessile glands and sunken, translucent glands | |
9 Corolla white (or with pink or purple flush); [collectively widespread]. | |
13 Leaves narrowly elliptic or rhombic to oblanceolate, not conspicuously falcate, (2.7-) 5-11 (-18) mm wide, (2.5-) 3.5-5 (-6)× as long as wide; leaf margins with (1-) 3-5 (-7) teeth per side; primary veins 3-5 (-7); mid-stem moderately to densely glandular pubescent (rarely glabrate); seeds (0.18-) 0.22-0.26 (-0.29) mm thick; [widespread] | |
13 Leaves linear, linear-lanceolate, to elliptic-lanceolate, often falcate, (1-) 2.5-4 (-4.5) mm wide, (5.5-) 6-9.5 (-11)× as long as wide; leaf margins with 0-2 (-3) teeth per side; primary veins 1 (-3); mid-stem glabrous; seeds (0.19-) 0.26-0.32 (-0.37) mm thick; [limestone cedar glades of n. AL and c. TN] |
4 Calyx lobes about equal, all shorter than the corolla tube; corolla 25-40 mm long; leaves to 15 mm wide | |
4 Calyx lobes distinctly unequal, all longer than the corolla tube; corolla 10-13 mm long; leaves to 5 mm wide | |
8 Leaves strongly basally disposed, usually all the leaves basal (or with significantly reduced cauline leaves); petals 3 or 4, scarious and translucent in texture or otherwise dull-yellow and inconspicuous; inflorescence a spike; [tribe Plantagineae] | |
10 Leaves whorled. | |
11 Aquatic; leaves 5-30 mm long, lanceolate, toothed to deeply dissected into linear segments; [tribe Gratioleae] | |
12 Petals 0; sepals 0, stamens 1; leaves both < 2 cm long and entire; [tribe Callitricheae] | |
12 Petals 4 or 5; sepals 4 or 5; stamens 2 or 4; leaves > 2 cm long, or serrate, or both. | |
16 Inflorescence compact, the inflorescence axis generally hidden by the closely packed and overlapping flowers; each flower subtended by large overlapping bracts | |
16 Inflorescence more diffuse, the inflorescence axis readily visible between the flowers; flowers lacking extra subtending bracts | |
18 Capsule turgid, roundish in ×-section; capsule longer than wide; leaves monomorphic; [collectively of many habitats and widespread]. | |
22 Corolla nearly radially symmetrical; corolla lobes about as long as the corolla tube; leaves palmately veined, with parallel veins diverging from the base, margins entire to crenulate; of aquatic to moist habitats, often somewhat succulent | |
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1 Leaves peltate. | |
2 Leaf blades orbicular in shape, ca. 1× as long as wide, at maturity floating on the water’s surface, emersed, or submersed; underwater portions of fresh plant not mucilaginous (though possibly with green algae, etc.). | |
5 Basal leaves variously shaped, > 10 mm long. | |
7 Inflorescence diffuse, a raceme or panicle with whorled branches or pedicels, the flowers widely spaced and white; leaves green, “wettable” | |
7 Inflorescence tightly packed with flowers, an elongate, golden yellow spadix; leaves blue-green, “unwettable” | |
10 Flowers 4-5-merous (sepals 4-5, petals 4-5, stamens 4-5); [Eudicots] | |
11 Leaves emersed or submersed, on stout, stiff petioles (the submersed and winter leaves cuneate-based and lanceolate); flowers 4-merous (sepals 4, petals 4, stamens 4); inflorescence a spike | |
11 Leaves floating, on slender, flexuous petioles (all leaves cordate-based); flowers 5-merous (sepals 5, petals 5, stamens 5); inflorescence an umbel | |
12 Perianth parts numerous (usually showing differentiation into sepals and petals, though often with some intergradation), borne in a spiral; stamens numerous; leaves usually > 10 cm long or > 10 cm wide, or both (a few northern species of Nymphaea with leaves as small as 2.5 cm × 2.5 cm); [Basal Angiosperms] | |
12 Perianth parts 3-6 (either differentiated or not into sepals and petals); stamens either 3, or 9-12 (-18), or >20; leaves 1-10 cm long, 1-10 cm wide; [Monocots]. | |
13 Perianth strongly differentiated, the 3 sepals green, leathery, and persistent, the 3 petals yellow or white, delicate, deciduous; stamens 20 or more | |
14 Flowers unisexual, white, the sepals and petals separate; stamens 3, 6, 9, 12, 15, or 18; leaves either with a central area of spongiform cells (most easily seen on the lower leaf surface) (Limnobium), or without spongiform cells (Ottelia) | |
14 Flowers bisexual, white to blue, the perianth segments united below into a perianth tube 3-45 mm long; stamens 3; leaves lacking a central area of spongiform cells |
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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. | |