4. Lithospermum latifolium Michx. (American gromwell)

L. officinale L. var. latifolium (Michx.) Lehm.

Map 1301, Pl. 308 i

Plants perennial herbs, with stout, somewhat woody taproots or short rhizomes. Stems 40–100 cm long, erect or ascending, solitary or few, unbranched or branched, moderately to densely pubescent with short, stiff, appressed-ascending, slender, usually minutely pustular-based hairs. Stem leaves 2–14 cm long, 8–60 mm wide, lanceolate to narrowly ovate, thin, angled or tapered at the base, tapered to a sharply pointed tip, the upper surface moderately roughened with minute, stiff, loosely appressed, pustular-based hairs and usually also sparse, longer hairs, dark green, the undersurface moderately to densely pubescent with short, fine, softer, loosely appressed hairs, grayish green, with 3–5 pairs of prominent, arched lateral veins. Inflorescences of solitary flowers in the upper leaf axils. Cleistogamous flowers not produced. Calyces 4–6 mm long at flowering, elongating to 5–8 mm at fruiting. Corolla 5–8 mm long, narrowly funnelform, white to greenish white, the tube 4–6 mm long, the lobes 1.0–1.5 mm long, entire. Stamens inserted near the middle of the corolla tube. Style 1–2 mm long. Nutlets 3.5–5.0 mm long, the tip more or less symmetrical, without an appendage at the attachment point, smooth or faintly pitted, white. 2n=28. May–June.

Uncommon in the northern half of the state (eastern U.S. west to South Dakota and Kansas; Canada). Mesic upland forests, mostly on north-facing slopes; also roadsides.

This species apparently is relatively uncommon throughout its range. Steyermark (1963) noted its superficial resemblance to Onosmodium molle ssp. occidentale, which differs in its usually paired scorpioid inflorescences and leaf venation strongly impressed on the upper surface and strongly ridged on the undersurface, in addition to its quite different flowers.