Flowers perfect. Petals involute in the bud. Stamens definite, mostly 6. Ovaries many in a simple circle on a flattened receptacle, forming flattened coriaceous achenes, which are dilated and 2–3-keeled on the back.—Roots fibrous. Leaves all from the root, several-ribbed, with connected veinlets. Scape with whorled panicled branches. Flowers small, white or pale rose-color. (The Greek name; of uncertain derivation.)
1. A. Plantàgo, L. Perennial by a stout proliferous corm; leaves long-petioled, ovate, oblong, or lanceolate or even linear, acute, mostly rounded or heart shaped at base, 3–9-nerved; panicle loose, compound, many-flowered (1–2° long); carpels obliquely obovate, forming an obtusely triangular whorl in fruit.—Shallow water and ditches, across the continent. Very variable as to foliage, but the leaves usually more broadly cordate-ovate than in Old World forms (var. Americànum, R. & S.); when growing under water thinner and narrowly lanceolate. (Eu., etc.)
2. SAGITTÀRIA, L. Arrow-head.
Flowers monœcious, or often diœcious in n. 1 and 4, and polygamous in n. 7. Petals imbricated in the bud. Stamens indefinite, rarely few. Ovaries many, crowded in a spherical or somewhat triangular depressed head on a globular receptacle, in fruit forming flat membranaceous winged achenes.—Marsh or aquatic, mostly perennial, stoloniferous herbs, with milky juice and fibrous roots; the scapes sheathed at base by the bases of the long cellular petioles, of which the primary ones, and sometimes all, are flattened, nerved, and destitute of any proper blade (i.e. are phyllodia); when present the blade is arrow-shaped or lanceolate, nerved and with cross-veinlets as in Alisma. Flowers produced all summer, whorled in threes, with membranous bracts; the sterile above. (Name from sagitta, an arrow, from the prevalent form of the leaves.)
§ 1. SAGITTARIA proper. Flowers monœcious, with the lower whorls pistillate, or diœcious; stamens few or numerous, covering the receptacle; sepals spreading or reflexed in fruit.
[*] Filaments numerous, narrow, as long as or longer than the linear-oblong anthers; bracts 3, distinct; fruiting heads larger.
1. S. variábilis, Engelm. Scape (¼–4° high) angled, with one or more of the lower whorls fertile; leaves very various, almost always sagittate; bracts mostly pointed; pedicels of the fertile flowers at least half the length of the sterile ones; petals wholly white; filaments glabrous, nearly twice the length of the anthers; achenes obovate (about 1´´ long), winged on both margins, with a long curved or usually horizontal beak ¼–{1/3} its length. (S. sagittæfolia, L., var. variabilis, M. Micheli.)—In water or wet places, very common; exceedingly variable in size and foliage, ordinarily with narrow halberd-shaped or sagittate leaves,—sometimes diœcious, with large, broad and obtuse leaves (var. obtùsa), or monœcious, with large, broad and acute leaves (var. latifòlia), or the narrow leaves with long and linear diverging lobes (var. angustifòlia), or with some leaves lanceolate or ovate-lanceolate, others more or less sagittate (var. diversifòlia), etc. Root propagating by stolons tuberiferous at the extremity.—The European species has the fertile pedicels only {1/3} or ¼ the length of the sterile; claws of the petals purple-tinged; filaments not longer than the anthers; and achenes almost orbicular, very broadly winged and with a short straight beak.
Var. pubéscens, Engelm. Upper part of petiole and scape and especially the orbicular-ovate obtuse bracts and sepals pubescent or woolly; beak of fruit horizontal.—N. J. and Penn. to Ga.
Var. (?) grácilis, Engelm. Lobes of the sagittate leaves very narrowly linear (½–2´´ wide); achene narrowly cuneate-obovate (2´´ long), the beak long, stout, and strongly recurved, the sides usually strongly 1–3-crested. (S. cristata, Engelm.?)—Mass. to western N. Y.; Iowa.