Burke: Sparganium androcladum vs. Sparganium natans

	Sparganium androcladum	Sparganium natans
		arctic bur-reed, small bur-reed
Habit		Dioecious, aquatic perennials from rhizomes, stems from floating and up to 10 dm. long to largely emersed and 1-3 dm. tall.
Leaves		Leaves floating to erect, 3-6 mm. broad, exceeding the inflorescence.
Flowers		Flowers in globose clusters toward the tip of the main stem; inflorescence simple, up to 6 cm. long, with 3-4 heads, the uppermost staminate or with both staminate and pistillate flowers; pistillate heads up to 12 mm. thick when mature, usually all sessile; stamens 3-5 with 3-5 minute, chaffy bracts; pistil 1, stigma 1.
Fruits		Fruit a nutlet-like achene with a stipe 1 mm. long, the body ellipsoid, 3 mm. long, the beak 1-1.5 mm. long.

	Sparganium androcladum	Sparganium natans
Flowering time		July-August
Habitat		Shallow water, mostly in mountain lakes, sometimes completely submersed.
Distribution	[WildflowerSearch map] [BONAP county map]	Occurring on both sides of the Cascades crest in Washington; Alaska to California, across the northern half of North America to the Atlantic Coast. [WildflowerSearch map] [BONAP county map]
Origin		Native
Conservation status		Not of concern
Sibling taxa	S. angustifolium, S. emersum, S. eurycarpum, S. fluctuans, S. natans	S. angustifolium, S. emersum, S. eurycarpum, S. fluctuans
Web links	Local Web sites: Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog. WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Sparganium androcladum

Sparganium natans

arctic bur-reed, small bur-reed

Habit

Dioecious, aquatic perennials from rhizomes, stems from floating and up to 10 dm. long to largely emersed and 1-3 dm. tall.

Leaves

Leaves floating to erect, 3-6 mm. broad, exceeding the inflorescence.

Flowers

Flowers in globose clusters toward the tip of the main stem; inflorescence simple, up to 6 cm. long, with 3-4 heads, the uppermost staminate or with both staminate and pistillate flowers; pistillate heads up to 12 mm. thick when mature, usually all sessile;

stamens 3-5 with 3-5 minute, chaffy bracts;

pistil 1, stigma 1.

Fruits

Fruit a nutlet-like achene with a stipe 1 mm. long, the body ellipsoid, 3 mm. long, the beak 1-1.5 mm. long.