7. Plantago major L. (common plantain, broad-leaved plantain, white man’s foot)

P. major var. paludosa Bég.

P. major ssp. pleiosperma Pilger

Pl. 487 a; Map 2226

Plants perennial (but often flowering the first year), with numerous, slender, fibrous roots, the rootstock unbranched and erect at the glabrous tip. Aerial stems absent. Leaves in a dense basal rosette, with short to long, winged and shallowly grooved petioles, usually green at the base, arched or spreading to loosely ascending. Leaf blades 4–18(–25) cm long, 1.5–11.0(–14.0) cm wide, elliptic to ovate to broadly ovate, rounded or broadly angled to a bluntly pointed tip, rounded or occasionally shallowly cordate at the base, the margins entire or occasionally with widely spaced, small teeth, the surfaces glabrous or especially the undersurface sparsely and inconspicuously short-hairy, appearing green to dark green, with mostly 3 or 5 main veins, these all arising from the blade base and appearing arched or curved. Inflorescences 1 to more commonly several or many per plant, terminal, elongate spikes, (3–)5–25 cm long, 4–9 mm in diameter, densely flowered for the entire length (the axis not visible between the flowers) or the lowermost flowers sometimes more widely spaced, the stalk 5–30 cm long, erect or strongly ascending at flowering and fruiting, glabrous or inconspicuously short-hairy, the axis solid, circular in cross-section. Bracts 1.2–2.0 mm long, similar in length, shorter than the flowers (usually shorter than the calyces), mostly broadly ovate, with broad, translucent margins and a prominently keeled, green midnerve, bluntly pointed or less commonly rounded at the tip, glabrous. Cleistogamous flowers absent. Calyces deeply 4-lobed (the 2 lobes adjacent to the bract not fused into a single structure), 1.5–2.5 mm long, actinomorphic, mostly broadly ovate, rounded or broadly angled to a bluntly pointed tip, the prominently keeled, green midnerve glabrous, the broad, translucent margins thin and papery. Corollas not noticeably zygomorphic, the lobes 0.7–1.2 mm long, lanceolate to narrowly ovate-triangular with a truncate base, sharply pointed at the tip, the margins entire, translucent white, all of the lobes spreading to reflexed at flowering, reflexed at fruiting. Stamens 4, the anthers horned. Fruits 2.0–3.5 mm long, rhombic-ovoid, circumscissile at about the midpoint. Seeds 6–18(–30) per fruit, 0.7–1.0 mm long, irregularly ovate to somewhat quadrate, angled, the surface lacking a well-defined flattened or concave area, otherwise finely ridged, dark brown to black, shiny. 2n=12, 24. May–October.

Introduced, uncommon in southern Missouri and in counties bordering the Missouri and Mississippi Rivers (native of Europe, Asia, introduced nearly throughout New World). Banks of streams and rivers; also farmyards, lawns, sidewalks, railroads, roadsides, and open, disturbed areas.

Plantago major is superficially very similar to the native P. rugelii, especially when depauperate or juvenile plants are present. Tessene (1968), who studied the genus in Wisconsin, noted that juvenile or depauperate plants were difficult to distinguish when in a vegetative state, but that larger or fertile plants could be distinguished by some combination of the following characters (the states for P. major listed first): 1) Leaf blades ovate, broadly rounded to cordate at the base vs. elliptic to broadly elliptic, mostly tapered at the base; 2) Leaf blade margins usually entire vs. usually with 3–7 small teeth on each side; 3) petiole bases usually green vs. usually reddish- or purplish-tinged; 4) main veins mostly 3 or 5 vs. mostly 5 or 7; 5) calyx lobes and bracts broadly ovate, broadly angled at the tips vs. narrowly lanceolate-triangular, tapered at the tip; 6) capsules rhombic-ovoid, dehiscent near the midpoint vs. narrowly ellipsoid or narrowly ovoid, dehiscent near the base; 7) seeds 6–18(–30) per fruit, 0.7–1.0 mm long vs. 4–10 per fruit, 1.5–2.5 mm long.

Steyermark (1963) noted that a complex series of subspecies and varieties have been named to account for morphological variation within the native range of the species. However, most North American botanists (and many in Europe) instead treat the taxon as a widespread, morphologically variable species without segregating infraspecific taxa.