OregonFlora: Elatine californica vs. Elatinaceae

	Elatine californica	Elatinaceae
	California waterwort	waterwort family
Habit	Plants 1.5–7 cm.	Herbs or subshrubs annual or short-lived perennials.
Stems	light green to green (reddish green); internodes 2–12 mm.	erect to prostrate, green; reddish green, or red.
Leaves	blades spatulate or elliptic, 3–12 mm; petioles 0.5–6 mm.	opposite; simple; tips acute, petiolate; stipules 2.
Inflorescences	peduncles recurved, usually > 1.5 mm.	axillary; cymes or flowers solitary; bracts absent, pedicelled.
Flowers	(0.1)1.5–4 mm; sepals 4, sometimes 1 smaller; petals 4; stamens 8; carpels 4.	bisexual; radial; bell- or urn-shaped; sepals 3–5, 1 smaller; free; petals 3–5; free or connate basally; nectaries 0; stamens 3–10; filaments free; anthers dehiscent by slits; pistils 1; ovaries superior; carpels 3–5; placentas axile; ovules 3–many per chamber; styles 3–5; stigmas 3–5.
Fruits	disk-shaped to compressed globose, 4-locular.	capsules.
Seeds	16–24, highly curved to nearly circular, 0.5–0.7 mm; surface pits 20–27 per row; length 1.2–2 × their width.	9–36.

	Elatine californica	Elatinaceae
Distribution	[WildflowerSearch map] [BONAP county map]	[BONAP county map]
Discussion	In or near puddles, ponds, reservoirs, lakes, and marshes. Flowering Mar–Aug. 50–1600 m. Col, ECas. CA, ID, NV, WA; northeast to MT, southeast to NM, south to Mexico. Native. Elatine californica can be distinguished from all other Elatine species in the Unites States by its four-merous flower parts and nearly circular seeds. Both morphological and molecular analyses (Razifard et al. 2017) support a close affinity between E. californica and E. hydropiper, which occurs in Central Asia, Europe, and North Africa.	Nearly worldwide in aquatic habitats. 2 genera. Elatinaceae is composed of aquatic species found near rivers as well as in wetlands, ponds, reservoirs, and lakes. Cleistogamous (i.e., non-opening, self-pollinating) flowers are very common in this family (Leach 1989; personal observation). A few species grow in rice fields in the United States and other countries (Rosman et al. 2016; DiTomaso & Healy 2007; Tucker 1986). Also, some species are popular aquarium plants (De Wit 1964).
Source	Flora of Oregon, volume 2, page 613 Hamid Razifard, Gordon Tucker, Donald Les	Flora of Oregon, volume 2, page 612
Sibling taxa	E. brachysperma, E. chilensis, E. rubella
Web links	Local floras: CA, OR, WA 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	Local floras: CA, OR Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Elatinaceae

California waterwort

waterwort family

Habit

Plants 1.5–7 cm.

Herbs or subshrubs annual or short-lived perennials.

Stems

light green to green (reddish green);

internodes 2–12 mm.

erect to prostrate, green; reddish green, or red.

Leaves

blades spatulate or elliptic, 3–12 mm;

petioles 0.5–6 mm.

opposite; simple;

tips acute, petiolate;

stipules 2.

Inflorescences

peduncles recurved, usually > 1.5 mm.

axillary;

cymes or flowers solitary;

bracts absent, pedicelled.

Flowers

(0.1)1.5–4 mm;

sepals 4, sometimes 1 smaller;

petals 4;

stamens 8;

carpels 4.

bisexual; radial; bell- or urn-shaped;

sepals 3–5, 1 smaller; free;

petals 3–5; free or connate basally;

nectaries 0;

stamens 3–10;

filaments free;

anthers dehiscent by slits;

pistils 1;

ovaries superior;

carpels 3–5; placentas axile;

ovules 3–many per chamber;

styles 3–5;

stigmas 3–5.

Fruits

disk-shaped to compressed globose, 4-locular.

capsules.

Seeds

16–24, highly curved to nearly circular, 0.5–0.7 mm;

surface pits 20–27 per row; length 1.2–2 × their width.

9–36.

Elatinaceae

Distribution

[WildflowerSearch map]

[BONAP county map]

Discussion

In or near puddles, ponds, reservoirs, lakes, and marshes. Flowering Mar–Aug. 50–1600 m. Col, ECas. CA, ID, NV, WA; northeast to MT, southeast to NM, south to Mexico. Native.

Elatine californica can be distinguished from all other Elatine species in the Unites States by its four-merous flower parts and nearly circular seeds. Both morphological and molecular analyses (Razifard et al. 2017) support a close affinity between E. californica and E. hydropiper, which occurs in Central Asia, Europe, and North Africa.

Nearly worldwide in aquatic habitats. 2 genera.

Elatinaceae is composed of aquatic species found near rivers as well as in wetlands, ponds, reservoirs, and lakes. Cleistogamous (i.e., non-opening, self-pollinating) flowers are very common in this family (Leach 1989; personal observation). A few species grow in rice fields in the United States and other countries (Rosman et al. 2016; DiTomaso & Healy 2007; Tucker 1986). Also, some species are popular aquarium plants (De Wit 1964).

Source

Flora of Oregon, volume 2, page 613
Hamid Razifard, Gordon Tucker, Donald Les

Flora of Oregon, volume 2, page 612

Sibling taxa

E. brachysperma, E. chilensis, E. rubella

Web links