OregonFlora: Elatine rubella

	Elatine rubella
	red-stem waterwort, southwestern waterwort
Habit	Plants 1.5–4 cm.
Stems	green to reddish green; internodes 1–7 mm.
Leaves	blades oblanceolate, 3–7 mm; petioles 0.5–1 mm.
Inflorescences	peduncles straight; < 1.5 mm.
Flowers	0.1–0.5 mm; sepals 3, sometimes 1 smaller; petals 3; stamens 3; carpels 3.
Fruits	compressed globose to globose, 3-locular.
Seeds	15–30, slightly curved to nearly straight; ~0.5 mm; surface pits 14–23 per row; length ~2 × their width.

	Elatine rubella
Distribution	[WildflowerSearch map] [BONAP county map]
Discussion	Emergent form in mudflats near reservoirs, submersed form in marshes. Flowering Apr–Jul. 1100–1600 m. BR, Owy. CA, ID, NV, WA; western North America. Native. Collections of Elatine rubella often are misidentified as E. chilensis, and vice versa, because of high similarity between the two species and the seed features not being readily visible. The emergent form of this species usually has more rigid stems and shorter internodes.
Source	Flora of Oregon, volume 2, page 614 Hamid Razifard, Gordon Tucker, Donald Les
Sibling taxa	E. brachysperma, E. californica, E. chilensis
Web links	Local floras: BC, CA, OR Local Web sites: CalFlora, CalPhotos, 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

Elatine rubella

red-stem waterwort, southwestern waterwort

Habit

Plants 1.5–4 cm.

Stems

green to reddish green;

internodes 1–7 mm.

Leaves

blades oblanceolate, 3–7 mm;

petioles 0.5–1 mm.

Inflorescences

peduncles straight; < 1.5 mm.

Flowers

0.1–0.5 mm;

sepals 3, sometimes 1 smaller;

petals 3;

stamens 3;

carpels 3.

Fruits

compressed globose to globose, 3-locular.

Seeds

15–30, slightly curved to nearly straight; ~0.5 mm;

surface pits 14–23 per row; length ~2 × their width.

Elatine rubella

Distribution

[WildflowerSearch map]

[BONAP county map]

Discussion

Emergent form in mudflats near reservoirs, submersed form in marshes. Flowering Apr–Jul. 1100–1600 m. BR, Owy. CA, ID, NV, WA; western North America. Native.

Collections of Elatine rubella often are misidentified as E. chilensis, and vice versa, because of high similarity between the two species and the seed features not being readily visible. The emergent form of this species usually has more rigid stems and shorter internodes.

Source

Flora of Oregon, volume 2, page 614
Hamid Razifard, Gordon Tucker, Donald Les

Sibling taxa

E. brachysperma, E. californica, E. chilensis

Web links