1	"Plant terrestrial, or if aquatic, strongly emergent"	2
1	"Plant aquatic, submersed or floating"	9
2	"Flowers all unisexual; inflorescence either a dense erect spike of staminate flowers directly distal to a spike of pistillate flowers, or a group of several spheric unisexual heads attached to a zigzag main axis, spikes or heads 1--4 cm diam"	Typhaceae
2	"Flowers bisexual or some or all unisexual; inflorescences of various types, generally < 1 cm diam if spike or head"	3
3	"Fruit a berry or capsule with 3--many seeds or breaking into 1-seeded mericarps; perianth segments 4--6, well developed --- actually in two whorls, but this may not be evident in open flowers"	4
3	"Fruit an achene or grain, 1-seeded; perianth inconspicuous or 0 or modified as +- conspicuous bristles"	6
4	"Leaves with expanded blades; perianth parts petal-like, white or cream"	"Ruscaceae {Maianthemum}"
4	"Leaves narrowly linear; perianth parts scale-like, green to +- red or brown"	5
5	"Inflorescence of 1--many flowers, variously clustered, subtended individually and/or in small groups by bracts; style 1, stigmas (2)3, linear, spreading; fruit a capsule"	Juncaceae
5	"Inflorescence a bractless raceme; stigmas 3 or 6, +- sessile, papillate or plumose; fruit breaking into mericarps"	"Juncaginaceae {Triglochin}"
6	"Inflorescence a bractless emergent spike of bisexual and sometimes staminate flowers, plus 2 submerged, long-styled, sessile pistillate flowers enclosed by leaf sheath at base of peduncle; stamen 1; stigma 1"	"Juncaginaceae {Triglochin scilloides}"
6	"Inflorescence 1--many spikelets with flowers individually subtended or enclosed by scale-like bracts; stamens (1)3(6); stigmas 2--3"	7
7	"Stem leafless, the leaves all basal, sometimes reduced to bladeless sheaths"	Cyperaceae
7	"Stem at least proximally leafy"	8
8	"Stems generally 3-angled (cylindric), generally solid; nodes not swollen; leaves generally 3-ranked; spikelet generally without 2 bractlets at base that do not directly subtend flower parts; each flower subtended by 1 bract (in _Carex_ and _Kobresia_ a second, generally hollow, +- flask-shaped bract [perigynium] surrounds or encloses each pistillate flower); perianth of generally inconspicuous to long-exserted bristles or 0; fruit an achene"	Cyperaceae
8	"Stems cylindric, the internodes generally hollow; nodes swollen, knot-like; leaves 2-ranked or not in obvious ranks; each spikelet generally with 2 bractlets [glumes] at base that do not directly subtend flower parts; each flower generally enclosed by 2 additional bractlets [lemma and palea]; perianth of 2 tiny scales or 0; fruit a grain"	Poaceae
9	"Plant raft-like, free-floating or stranded on shore or drying mud, either plant body 0.4--10 mm, not differentiated into stems and leaves with roots unbranched or 0, or plant with floating rosette of widely wedge-shaped, velvety-hairy leaves and many fine, branched roots"	Araceae
9	"Plant not raft-like, generally rooted, >> 1 cm, differentiated into stems and leaves, not forming floating rosettes; roots generally present, often branched; leaves linear, glabrous"	10
10	"Leaves opposite or whorled (occasionally alternate at some nodes), all cauline"	11
10	"Leaves alternate, basal and/or cauline"	12
11	"Leaf coarsely to finely toothed (teeth sometimes appearing +- 0 to naked eye); stipules 0 (leaf base may have ear-like lobes); fruit without a stiff beak"	"Hydrocharitaceae {Najas}"
11	"Leaf entire; stipules fused to blade or free, membranous, entire; fruit with a stiff beak"	"Zannichelliaceae {Zannichellia palustris}"
12	"Leaves all +- basal, sheaths overlapping and blades emerging at different levels, but stem internodes very short, not evident --- pistillate flowers paired, axillary, submersed, style 6--20 cm, thread-like, stigma floating, head-like; staminate and bisexual flowers in peduncled spike"	"Juncaginaceae {Triglochin scilloides}"
12	"Leaves basal and cauline or all cauline, stem internodes evident"	13
13	"Inflorescence a dense, spheric head"	"Typhaceae {Sparganium}"
13	"Inflorescence a spike or flowers solitary"	14
14	"Inflorescence a flattened spike enwrapped by a sheathing bract; subtidal or intertidal seawater or brackish water of bays and estuaries"	Zosteraceae
14	"Inflorescence a cylindric spike, short- to long-stalked; freshwater, brackish, or inland saltwater habitat --- carpels actually free but easily misinterpreted"	15
15	"Sepals 4; stamens 4; fruits sessile; fresh water in lakes, streams, ponds"	Potamogetonaceae
15	"Sepals 0; stamens 2; fruits on thread-like stalks; fresh to brackish or salt water in coastal to inland areas"	"Ruppiaceae {Ruppia}"