12. Plantago wrightiana Decne. (Wright’s plantain)
Pl. 488 e, f;
Map 2231
Plants annual or
short-lived perennial, with taproots and later sometimes a short, sometimes
branched rootstock. Aerial stems absent or very short and inconspicuous (to 5
cm long with age), then unbranched. Leaves in a dense basal rosette (aerial
stem leaves alternate but crowded), sessile or with a short, poorly
differentiated petiole, strongly ascending. Leaf blades 3–12(–18) cm long, 1–7
mm wide, linear or narrowly oblanceolate (those of seedlings and overwintering
rosettes sometimes narrowly obovate), angled or tapered to a bluntly or more
commonly sharply pointed tip, long-tapered at the base, the margins entire,
hairy, the upper surface glabrous or occasionally sparsely short-hairy, usually
appearing dark green (usually darkening upon drying), the undersurface
moderately to densely pubescent with shaggy or woolly hairs, appearing
uniformly gray, with 1 main vein. Inflorescences 1 to several per plant,
terminal, elongate spikes, 1–10 cm long 7–9 mm in diameter, densely flowered
(the axis not visible between the flowers), the stalk 5–20 cm long, hairy, the
axis solid. Bracts 2–3 mm long, similar in length, shorter than to about as
long as the flowers, triangular-ovate, with relatively broad, translucent
margins and a thick, green midnerve, angled to a bluntly or sharply pointed
tip, glabrous or hairy along the midnerve. Cleistogamous flowers usually
abundant. Calyces deeply 4-lobed, 2.7–3.5 mm long, slightly zygomorphic,
narrowly oblong-obovate to obovate, rounded at the tip, the upper pair with
somewhat broader, papery margins than the lower pair. Corollas zygomorphic, the
lobes 2.4–3.2 mm long, broadly ovate with a shallowly cordate base (the lateral
lobes asymmetric), rounded to very bluntly pointed at the tip, the margins
entire, each with an inconspicuous brown base, otherwise white to somewhat
translucent, the upper lobe slightly shorter than the others and ascending at
flowering, the other lobes spreading, spreading to reflexed after flowering.
Stamens 4, the anthers horned. Fruits 3.5–4.2 mm long, ellipsoid to ovoid,
circumscissile below the midpoint. Seeds usually 2 per fruit, 2.5–3.2 mm long,
oblong-elliptic with a shallow groove around the circumference just below the
midpoint, the surface shallowly to deeply concave on 1 side, otherwise finely
pitted, reddish brown, lighter in the concave portion. 2n=20.
May–August.
Introduced,
known thus far only from the city of St. Louis (native of Arizona, New Mexico,
Oklahoma, Texas; Mexico; introduced widely in the southeastern U.S. and
Missouri). Railroads.
This species was
discovered in Missouri by Viktor Mühlenbach during his inventories of the St.
Louis railyards. It was first reported by Steyermark (1963) in the supplement
of species documented too late for inclusion in the main text of his Flora
of Missouri.