Elatine brachysperma |
Elatine ambigua |
|
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short-seed waterwort |
Asian waterwort |
|
Habit | Herbs, submersed or emersed on wet substrates, 0.5–3(–5) cm. | Herbs, submersed, 1.5–4(–8) cm. |
Stems | ascending or prostrate, branched. |
prostrate or erect, branched. |
Leaves | reddish green; stipules lanceolate, 0.5–0.6 mm, margins dentate, apex acute; petiole (0–)1–3 mm; blade narrowly oblong to ovate, 3–8 × 1–3 mm, base cuneate to rounded, apex rounded to obtuse. |
green; stipules lanceolate, 1 mm, margins dentate, apex acute; petiole 0.1–1 mm; blade lanceolate or oblong-elliptic, 2–6 × 0.5–1.5 mm, base cuneate, apex obtuse to acute. |
Pedicels | 0–0.4 mm, erect. |
0.5–2.5 mm, recurved in fruit. |
Flowers | sepals (2–)3, equal, oblong-ovate, 1.1–1.3 × 0.3 mm; petals 3, pinkish, elliptic or ovate, 1–1.5 × 0.5 mm; stamens 3; styles 3. |
sepals 3, equal, oblong-ovate or broadly lanceolate, 0.5 × 0.3 mm; petals 0 or 3, reddish, long-elliptic or ovate, 1–1.5 × 0.5 mm; stamens 3; styles 3. |
Capsules | globose, 3-locular, 1.1–1.7 mm diam. |
oblong-ovoid, 3-locular, 1 mm diam. |
Seeds | (6–)10–15 per locule, oblong, straight or curved to 30°, 0.3–0.5 × 0.1–0.3 mm; pits ± round, length 1–2 times width, in 6(–8) rows, (9–)14–17 per row. |
10 per locule, narrowly oblong, straight or curved 15–30°, 0.3 × 0.1 mm; pits obscure, round, length 1–4 times width, in 6 rows, 19–25(–30) per row. |
Elatine brachysperma |
Elatine ambigua |
|
Phenology | Flowering summer–early fall. | Flowering late spring–summer. |
Habitat | Muddy shores, often of ponds or reservoirs. | Pools, marshy places, rice fields. |
Elevation | 0–1500(–2200) m. (0–4900(–7200) ft.) | 0–100 m. (0–300 ft.) |
Distribution |
AL; AZ; CA; GA; IL; LA; MT; NE; NM; NV; OH; OK; OR; TX; WA; WY; BC; Mexico (Baja California); South America (Argentina)
|
CA; CT; MA; SC; VA; s Asia; se Asia [Introduced in North America; introduced also in Europe, s Pacific Islands, Australia] |
Discussion | Elatine ambigua is a popular aquarium plant usually misidentified as E. trianda. It is also a common weed in rice fields. This species probably was introduced to California, South Carolina, and Virginia through rice farming. Its introduction to Connecticut and Massachusetts probably was through aquarium disposal or fish stocking. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 12, p. 353. | FNA vol. 12, p. 352. |
Parent taxa | Elatinaceae > Elatine | Elatinaceae > Elatine |
Sibling taxa | ||
Synonyms | Alsinastrum brachyspermum, E. obovata, E. triandra var. brachysperma, E. triandra var. obovata, Potamopitys brachysperma | |
Name authority | A. Gray: Proc. Amer. Acad. Arts 13: 361, 363. (1878) | Wight: Bot. Misc. 2: 103, suppl. plate 5. (1830) |
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