Acorus americanus
American sweet-flag, belle-angélique, several-vein sweetflag, sweet-flag
basally white with pink or red, otherwise bright green;
major veins 2–6, ± equally raised above leaf surface;
cross section swollen in center, gradually tapering to ends.
2–3 mm;
pollen grains usually deeply staining in aniline blue.
obpyramidal, 4–6 mm.
(1–)6(–14), tan, narrowly oblong to obovate, (2–)3–4 mm.
leaves to 1.45 m; sheathing base (proximal part of leaf) 18.1–51.8(–58.8) cm;
distal part of leaf 31.2–88.6(–100.4) × 0.3–1.2 cm, usually slightly longer to more than 2 times length of distal leaf, margins usually entire.
leaf (46–)56.8–148(–166.7) cm, usually equal to or slightly longer than vegetative leaves; sheathing base (20.9–)25.3–74.1(–100.2) cm;
distal part of leaf (20.9–)27.9–77.9(–92.6) × 0.3–1.3 cm.
3.3–7.4(–8.7) cm × 4.7–10(–13.3) mm at anthesis; fruiting spadix 3.5–7.8(–8.8) cm × 6.9–18.2 mm.
= 24.
Acorus americanus
Acorus americanus, a fertile diploid, occurs from northeastern United States across Canada and the northern plains. Specimens from central Siberia with similar leaf venation were examined, and the species is perhaps holarctic in distribution. Examination of additional material is necessary to determine if northern Asian diploid plants are conspecific with A. americanus. In North America, Native Americans probably played a significant role in the present-day distribution of A. americanus because sweet-flag rhizomes and plants were valued by many groups and were objects of trade. Disjunct populations occur in localities that are often near old Native American village sites or camping areas (M. R. Gilmore 1931).
Acorus americanus is susceptible to infection by Uromyces sparganii (Uredinales).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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