Contains 9 genera and 15 accepted taxa overall.
This family is completely databased for all specimens.
Characteristics
HYDROCHARITACEAE
Monocot
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Classification
ALISMATALES
HYDROCHARITACEAE
[Family identification key]
1. Leaves petiolate or in a pseudowhorl terminating an elongate naked erect stem, the blade generally oblong to narrowly elliptic or ovate
2
1. Leaves sessile (not pseudowhorled and terminating an elongate naked stem), generally linear, linear-lanceolate, to oblong
4
2. Leaf blades oblong to narrowly elliptic, 0.6-8 mm wide; brackish to marine
2. Leaf blades generally ovate, 15-150 mm wide; freshwater
3
3. Leaf blades 1-10 cm long, usually strongly cordate at base, some with aerenchyma on lower surface
3. Leaf blades 7-20 cm long, mostly truncate, cuneate, to subcordate at base, without aerenchyma on lower surface
4. Leaves basal, 6-100 cm long
5
4. Leaves on an elongate stem, 0.4-3 cm long
6
5. Rhizome scaly or fibrous, stout, with short internodes; leaves 2-ranked and flattened together at base, entire or subtly serrulate distally, without lacunae; fruits spheric, echinate; brackish to marine
5. Rhizomes naked, slender, elongate; leaves spirally arranged, serrulate to entire, fruits cylindric to ellipsoid, ridged; freshwater to brackish
6. Leaves 0.1-2.5(4) mm wide, opposite (sometimes crowded and pseudowhorled)
6. Leaves 2-4(5) mm wide, whorled at most nodes
7
7. Leaves 10-40 mm long, (2)5-8(10) per node
7. Leaves 5-15(20) mm long, 2-8 per node
8
8. Leaf margins and midveins entire; intravaginal scales squamules entire or fringed with clear marginal hairs
8. Leaf margins and the lower side midvein serrulate or prickly; intravaginal squamules fringed with orange-brown hairs