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1 Leaves broad, < 4× as long as wide. |
..2 Floating leaves peltate |
..2 Floating or emersed leaves cuneate to rounded at base. |
....3 Floating leaves diamond-shaped, prominently serrate |
....3 Floating or emersed leaves elliptic or suborbicular. |
......4 Leaves emersed, lanceolate to narrowly elliptic; flowers 5-merous; [Eudicots] |
......4 Leaves emersed or floating, suborbicular or elliptic (if emersed, then suborbicular; flowers 3-merous; [Monocots]. |
........5 Leaves emersed, suborbicular |
........5 Leaves floating, elliptic |
1 Leaves narrow, > 4× as long as wide. |
..........6 Leaves 0.3-1.4 cm long, very numerous and tightly spaced |
..........6 Leaves 2-35 cm long, fewer and scattered along the stem. |
............ 7 Leaf divided into a sheath and blade, with a ligule 0.5-8 mm long at the juncture; inflorescence a spike, raceme, or panicle of spikelets |
............ 7 Leaf not divided into a sheath and blade, but if basally sheathing lacking a ligule (though sometimes with 1-2 conspicuous stipules); inflorescence various, but not as above. |
............ ..8 Leaves terete, to 35 cm long, 0.3-2 mm wide; plants of marine habitats, growing submersed in salt water; [FL and the Gulf Coast of AL, MS, and LA] |
............ ..8 Leaves flat or terete, to 200 cm long; plants of fresh or brackish waters (if of marine waters, Zostera, the leaves obviously flat, 1.5-6 mm wide); [collectively widespread]. |
............ ....9 Leaves filiform, terete or nearly so; stipules present, adnate to the leaf base and forming a sheath around the stem > 10 mm long. |
............ ......10 Stipule free at its tip, the sheathing portion not appearing inflated; flowers > 2, in an interrupted spike |
............ ......10 Stipule adnate its entire length to the leaf base, appearing inflated; flowers usually 2, on a flexous, elongate peduncle |
............ ....9 Leaves flat; stipules absent, or if present, either free or adnate to the leaf base and forming a sheath for < 10 mm. |
............ ........11 Leaves lacking a midvein; perianth parts 6, yellow |
............ ........11 Leaves with a midvein; perianth parts 0 or 4, variously colored (not yellow). |
............ ..........12 Plants pubescent (at least on the upper stem); leaves pinnately veined; [Eudicots] |
............ ..........12 Plants nearly or entirely glabrous; leaves with parallel venation; [Monocots]. |
............ ............ 13 Inflorescences of flowers solitary or in 2-4 flowered racemes, axillary; spathe lacking; perianth conspicuous with 3 pink to purple petals |
............ ............ 13 Inflorescence a spike, terminal or axillary; with or without a spathe; perianth lacking. |
............ ............ ..14 Inflorescence a cylindrical, interrupted spike, lacking a spathe; leaves either parallel-margined or variously with a narrow blade differentiated from a petiole; [fresh to brackish waters] |
............ ............ ..14 Inflorescence either a flattened spike sheathed by a spathe-like bract, or solitary; leaves parallel-margined, to 20 dm long; [saline (marine) to brackish waters]. |
............ ............ ....15 Leaves with a notched or tricuspidate apex; flowers solitary; [e. NC southward] |
............ ............ ....15 Leaves with a rounded apex; flowers in a flattened spike sheathed by a spathe-like bract; [e. NC northward] |