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1 Individual leaves > 2 cm wide. |
..2 Leaves obovate, cuneate at the base, sessile, pale green; plants floating because of “unwettable” leaf surfaces |
..2 Leaves orbicular, cordate or truncate at the base, petiolate, dark green; plants floating because of petioles inflated as bladders, or inflated cells centrally located on each leaf. |
....3 Petiole terete, not air-filled; plants floating because of inflated cells centrally located on each leaf (most easily seen on the lower surface) |
....3 Petiole conspicuously expanded into an air-filled bladder; plants floating because of petioles inflated as bladders |
1 Individual leaves or “fronds” < 2 cm wide, or leaves absent. |
......4 Submersed portions of the plant with small (< 4 mm in diameter) bladder-traps |
......4 Submersed portions of plant lacking small bladder traps. |
........5 Plants dichotomously forked, upper surface of leaves velvety or variously hairy |
........5 Plants unbranched, or if branched, irregularly so; upper surface of leaves glabrous, waxy. |
..........6 Plant thalloid; flowers embedded in the thallus in reproductive pouches |
..........6 Plant with well-differentiated stems and leaves, the leaves obviously and alternately spaced along a well-developed stem; flowers axillary |
1 Leaves thread-like or quill-like, about as thick as wide. |
..2 Plants bulbous at base, and with the leaf bases expanded and containing sporangia; plant tufted or with very short rhizomes; [Lycophytes] |
..2 Plants either somewhat bulbous or not at the base, the leaf-bases not containing sporangia; plant rhizomatous; [Pteridophytes, Eudicots, Monocots]. |
....3 New leaves unfurling with circinate vernation (a fiddlehead); plants reproducing by spores, from sporocarps on short stalks from the rhizome; [Pteridophytes] |
....3 New leaves lacking circinate vernation; plants reproducing by flowers and seeds. |
......4 Perianth differentiated, with either 3 sepals and 3 petals or 5 sepals and 5 petals; stamens either 7-many or stamens 4. |
........5 Sepals 3; petals 3; stamens 7-many; [Monocots] |
........5 Sepals 5; petals 5; stamens 4; [Eudicots] |
......4 Perianth undifferentiated, with 0, 3, or 6 tepals; stamens 1, 2, or 3; [Monocots]. |
..........6 Gynoecium of 2 or more pistils, each pistil with 1 carpel and with 1 stigma |
..........6 Gynoecium of 1 pistil, each pistil with (2-) 3 carpels and (2-) 3 stigmas. |
............ 7 Fruit an achene; perianth absent |
............ 7 Fruit a capsule; perianth of 6 tepals |
1 Leaves ribbon-like or strap-like, distinctly flattened (sometimes only near the tip of the leaf). |
............ ..8 Subterranean portions of plant bearing bladder-traps; flowers yellow or purple, bilaterally symmetrical |
............ ..8 Subterranean portions of plant lacking bladder traps; flowers white, green, gray, radially symmetrical (except bilaterally symmetrical in Glossostigma in PHRYMACEAE). |
............ ....9 Leaves broadened towards the tip; [Monocots, Eudicots]. |
............ ......10 Flowers 3-merous; [Monocots] |
............ ......10 Flowers 4- or 5-merous; [Eudicots]. |
............ ........11 Leaves phyllodial, with obvious cross-partitions (septa); leaves alternate |
............ ........11 Leaves not phyllodial; leaves opposite |
............ ....9 Leaves parallel-margined or tapering towards the apex over much of their length; [Monocots]. |
............ ..........12 Leaves tapering towards the apex over much of their length; plant either tufted and not rhizomatous, or short rhizomatous;. |
............ ............ 13 Plant tufted, not rhizomatous; leaves spreading radially; inflorescence a tightly button-like head of very numerous small flowers, white, gray, tan, yellowish, or blackish; roots thickened, septate (not requiring magnification), unbranched |
............ ............ 13 Planted short-rhizomatous; leaves distichous, equitant; inflorescence either a subglobular, ovoid, or cylindrical head, of spirally imbricate scales, or a diffuse corymb; roots not thickened, not septate, branched. |
............ ............ ..14 Inflorescence a diffuse corymb; rhizomes and roots bright red |
............ ............ ..14 Inflorescence a subglobular, ovoid, or cylindrical head of spirally imbricate scales subtending individual flowers; rhizomes and roots not bright red |
............ ..........12 Leaves parallel-margined; plant usually rhizomatous. |
............ ............ ....15 Plants of marine habitats, growing submersed in salt water; [FL and the Gulf Coast of AL, MS, and LA] |
............ ............ ....15 Plants of freshwater or slightly to somewhat brackish habitats; [collectively widespread]. |
............ ............ ......16 Leaves lacking any midvein; flowers and fruits in globose heads |
............ ............ ......16 Leaves with a midvein; flowers and fruits solitary or in diffuse inflorescences. |
............ ............ ........17 Leaves with a distinct, broad lacunar band along the midvein |
............ ............ ........17 Leaves lacking a distinct lacunar band along the midvein. |
............ ............ ..........18 Stamens 3 |
............ ............ ..........18 Stamens >6 |
1 Leaves (or leaf-like adventitious roots) 1-pinnately compound or divided (with a central axis bearing pinnae, the pinnae not further divided). |
..2 Leaves crowded at the upper end of the stem, supported by inflated branches |
..2 Leaves (or leaf-like adventitious roots) spaced along the stem, no branches inflated. |
....3 Emersed leaves diamond-shaped, the blade < 2× as long wide, serrate only in the upper portion of its length |
....3 Emersed leaves lanceolate, the blade > 4× as long as wide, serrate along its length |
1 Leaves dichotomously or otherwise complexly (2-3×) compound or divided. |
......4 Plants bearing numerous bladder-like traps |
......4 Plants lacking bladder-like traps. |
........5 Leaves alternate; leaf segments complexly (but not dichotomously) branched. |
..........6 Leaf dissection 2-pinnate to 3-pinnate; flowers in racemes; petals 4, white |
..........6 Leaf dissection 2-ternate to 3-ternate; flowers solitary; petals 5, yellow or white |
........5 Leaves opposite or whorled; leaf segments dichotomously branched. |
............ 7 Leaves whorled; leaf segments entire or toothed with denticles. |
............ ..8 Leaf segments toothed with denticles |
............ ..8 Leaf segments entire |
............ 7 Leaves opposite; leaf segments entire. |
............ ....9 Leaves sessile |
............ ....9 Leaves petiolate |