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acid-water arrowhead, Engelmann's arrowhead

Kansas arrowhead

Habit Herbs, perennial, to 70 cm; rhizomes absent; stolons present; corms present. Herbs, perennial, to 90 cm; rhizomes absent; stolons present; corms present.
Leaves

emersed;

petiole triangular, 10–40 cm;

blade sagittate, 4.5–10 × 0.2–2 cm, basal lobes ± equal to remainder of blade.

emersed;

petiole triangular, 15–54 cm;

blade lanceolate to ovate, 5–20 × 1–10.5 cm.

Inflorescences

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.

racemes, rarely panicles, of 2–11 whorls, emersed;

bracts scarcely connate proximally, linear to lanceolate, 10–30 mm, delicate, not papillose; fruiting pedicels spreading to ascending, cylindric, 1.5–3.5 cm.

Flowers

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.

to 23 mm diam.;

sepals recurved, not enclosing flower or fruiting head;

filaments linear, shorter than anthers, glabrous;

pistillate pedicellate, without ring of stamens.

Fruiting

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.

heads 0.8–1.2 cm diam;

achenes cuneate-obovoid, abaxially keeled, 1.5–2.1 × 0.8–1.5 mm, beaked;

faces not tuberculate, wings 0–1, ± entire, glands absent;

beak lateral, horizontal or incurved, 0.1–0.2 mm.

2n

= 22.

Sagittaria engelmanniana

Sagittaria ambigua

Phenology Flowering late spring–summer (Jun–Sep). Flowering spring–summer (Apr–Sep).
Habitat Acid waters of ponds, lakes, bogs, and streams Pond and lake shores, shallow water, ditches, and damp areas
Elevation 0–1100 m (0–3600 ft) 100–1000 m (300–3300 ft)
Distribution
from FNA
AL; CT; DE; FL; GA; MA; MD; MS; NC; NJ; NY; PA; RI; SC; VA; ON
[WildflowerSearch map]
[BONAP county map]
from FNA
IL; IN; KS; MO; OK
[BONAP county map]
Discussion

Of conservation concern.

(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
S. ambigua, S. australis, S. brevirostra, S. cristata, S. cuneata, S. demersa, S. fasciculata, S. filiformis, S. graminea, S. guayanensis, S. isoetiformis, S. kurziana, S. lancifolia, S. latifolia, S. longiloba, S. montevidensis, S. papillosa, S. platyphylla, S. rigida, S. sanfordii, S. secundifolia, S. subulata, S. teres
S. australis, S. brevirostra, S. cristata, S. cuneata, S. demersa, S. engelmanniana, S. fasciculata, S. filiformis, S. graminea, S. guayanensis, S. isoetiformis, S. kurziana, S. lancifolia, S. latifolia, S. longiloba, S. montevidensis, S. papillosa, S. platyphylla, S. rigida, S. sanfordii, S. secundifolia, S. subulata, S. teres
Name authority J. G. Smith: Memoirs of the Torrey Botanical Club 5: 25. (1894) J. G. Smith: N. Amer. Sagittaria. 22, plate 17. (1894)
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