Sp. Pl. 1: 114. 1753.
Perennials, rarely annuals; caudex absent or well developed, conspicuous, glabrous or hairy; roots taproots, thick. Stems 0–40 mm, usually branched. Leaves 10–220 × (1–)10–15 mm; blade linear to lanceolate, margins entire or toothed, veins not conspicuous, surfaces glabrous, sometimes hairy. Scapes 40–120 mm, glabrous or hirsute. Spikes greenish or brownish, (15–)50–200(–290) mm, densely or loosely flowered; bracts broadly ovate, 1.5–4(–6) mm, length 0.8–1.2 times sepals. Flowers: sepals 1.5–3.5 mm; corolla radially symmetric, tube hairy, lobes reflexed, 1–1.5 mm, base obtuse; stamens 4. Seeds 1–3, 1.5–3 mm. 2n = 24.
Phenology: Flowering summer.
Habitat: Marine shorelines, crevices of large rocks in sea spray, coastal and inland salt marshes, alkaline and saline flats, roadsides.
Elevation: 0–800 m.
Greenland, St. Pierre and Miquelon, Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., P.E.I., Que., Sask., Yukon, Alaska, Calif., Conn., Maine, Mass., N.H., N.J., N.Y., Oreg., R.I., Va., Wash., Mexico, Central America, South America, Eurasia, Africa.
Plantago maritima has been reported from Utah; no specimen supporting that report has been found.
Since the 1930s, when Plantago maritima was shown to have high levels of phenotypic plasticity (J. W. Gregor and J. M. S. Lang 1950), it usually has been accepted in a broad sense. That approach is followed here, with all dwarf and loose-flowered forms (such as P. borealis and P. decipiens, respectively) included under this name.