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Zannichellia palustris - horned pondweed

Scientific Family
Zannichelliaceae
Synonyms
Zannichellia major
Plant type
Forbs and Subshrubs
Origin
Native
Lifecycle
Perennial
Height
Length to 40 inches
Riparian
Yes

Aquatic; linear leaves appear to be whorled about the stem; fruits on small stems in leaf whorls; fruits have horn-like appendages on margins.

Submerged aquatic plant of ponds and slow streams; sparsely branched stems; flat, filiform, 1-nerved leaves; male and female flowers in the same leaf axils enclosed by a sheath while in bud.

Habitat

Brackish or fresh waters of streams, lakes, or estuaries.

Plant Community
Riparian
Low elevation
1500
High elevation
4600

Flower Characteristics

Small, lacking sepals and petals; solitary or clustered at the leaf bases. Male and female flowers are separate in the same leaf axils.

Flower color
Greenish
Flower shape
Regular
Tubular
No
First bloom month
May
Last bloom month
September
Flower clusters
Elongated

Leaf and Stem Characteristics

Submersed thread-like leaves, smooth edged; oppositely-arranged (may appear whorled); leaf has a central vein; 1/16 to 4 inches long and less than 1/16 inch wide. Completely submersed weak stems; branched, thin, and thread-like.

Leaf type
Simple
Leaf color
Light to medium green
Leaf shape
Narrow
Leaf margin
Smooth
Leaf attachment
Opposite
Leaves clasp
No
Leaf hairs
Stems
Spines
No

Fruit and Seed Characteristics

Tiny, banana shaped; less than 1/16 inch long with a conspicuous hooked beak measuring less than 1/16 inch long and found in leaf axils.

Fruit type
Achene