Sagittaria platyphylla |
Sagittaria engelmanniana |
|
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delta arrowhead |
acid-water arrowhead, Engelmann's arrowhead |
|
Habit | Herbs, perennial, to 150 cm; rhizomes absent; stolons present; corms present. | Herbs, perennial, to 70 cm; rhizomes absent; stolons present; corms present. |
Leaves | submersed and emersed; submersed sessile, phyllodial, flattened, to 26 × 0.5 cm; emersed with petiole ± triangular, 21–70.5 cm, blade linear-ovate to ovate, 4.6–16.4 × 0.7–6.1 cm. |
emersed; petiole triangular, 10–40 cm; blade sagittate, 4.5–10 × 0.2–2 cm, basal lobes ± equal to remainder of blade. |
Inflorescences | racemes, of 3–9 whorls, emersed, 2.5–10 × 2–4.5 cm; peduncles 22–60 cm; bracts connate more than ¼ total length, lanceolate, 3–5.5 mm, delicate, not papillose; fruiting pedicels spreading to recurved, cylindric, 0.5–3 cm. |
racemes, of 2–4 whorls, emersed, 5–14 × 2–4 cm; peduncles 20–38 cm; bracts distinct or if connate, then less than ¼ total length, lanceolate, 5–25 mm, not papillose; fruiting pedicels spreading, cylindric, 1.5–3.5 cm. |
Flowers | to 1.8 cm diam.; sepals spreading to recurved, not enclosing flower or fruiting head; filaments dilated, longer than anthers, pubescent; pistillate pedicellate, without ring of sterile stamens. |
to 30 mm diam.; sepals recurved to spreading, not enclosing flower or fruiting head; filaments linear, longer than to equal length of anther, glabrous; pistillate pedicellate, without ring of sterile stamens. |
Fruiting | heads 0.7–1.2 cm diam.; achenes oblanceoloid, not abaxially keeled, 1.2–2 × 0.8–1.2 mm, beaked; faces tuberculate, wings absent, glands absent; beak lateral, horizontal to erect, 0.3–0.6 mm. |
heads 1–1.8 cm diam.; achenes cuneate to obovoid, without abaxial keel, 2.4–4 × 1.5–3.8 mm, beaked; faces not tuberculate, wings 1–3, ± entire, glands 1–2; beak lateral, obliquely ascending, (0.7–)1–2.1 mm. |
2n | = 22. |
= 22. |
Sagittaria platyphylla |
Sagittaria engelmanniana |
|
Phenology | Flowering summer–fall. | Flowering late spring–summer (Jun–Sep). |
Habitat | Streams and lakes | Acid waters of ponds, lakes, bogs, and streams |
Elevation | 0–900 m (0–3000 ft) | 0–1100 m (0–3600 ft) |
Distribution |
AL; AR; FL; GA; IL; KY; LA; MO; MS; OH; OK; PA; TN; TX; WV; Mexico (Nuevo León Mexico, sw Mexico); Central America (Panama)
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AL; CT; DE; FL; GA; MA; MD; MS; NC; NJ; NY; PA; RI; SC; VA; ON
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Discussion | Sagittaria platyphylla has been accepted at the variety level, i.e., Sagittaria graminea var. platyphylla (C. Bogin 1955; J. W. Wooten 1973; E. O. Beal et al. 1982). After studying dozens of populations in the field from much of its range and hundreds of herbarium specimens, we have concluded that this taxon should be recognized at the specific level instead, a conclusion supported by cladistic analyses of morphologic characters (R. M. Kortright 1998) (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 22. | FNA vol. 22. |
Parent taxa | Alismataceae > Sagittaria | Alismataceae > Sagittaria |
Sibling taxa | ||
Synonyms | S. graminea var. platyphylla, S.. mohrii | |
Name authority | (Engelmann) J. G. Smith: N. Amer. Sagittaria. 29. (1894) | J. G. Smith: Memoirs of the Torrey Botanical Club 5: 25. (1894) |
Web links |