4. Campanula rotundifolia L. (harebell, bluebell)

Pl. 330 a, b; Map 1407

Plants slender perennial herbs, with shallow roots and slender rhizomes and/or stolons. Stems 20–70 cm long, erect to loosely ascending, but not reclining on adjacent plants, often slightly 3-angled, glabrous or inconspicuously hairy in longitudinal lines, unbranched or sparingly branched toward the tip. Basal leaves often absent at flowering, with a long, slender petiole 2–3 cm long, the blade 0.5–1.0 cm long, 0.5–0.8 cm wide, broadly ovate to nearly circular, shallowly cordate, rounded, or broadly angled at the base, rounded or angled to a bluntly or sharply pointed tip, the margins entire or few-toothed, the surfaces glabrous. Stem leaves gradually reduced from near the stem base to the tip, long-petiolate to sessile, the blade 3–6 cm long, those of the lower leaves narrowly elliptic to oblanceolate, those of the upper leaves narrowly lanceolate to linear, angled or short-tapered at the base, tapered at the tip, the margins entire, the surfaces glabrous. Inflorescences of 3–8-flowered, open, nodding racemes, less commonly paniculate (of solitary flowers elsewhere). Calyx tube 2–3 mm long, the lobes 4–5 mm long, linear. Corolla bell-shaped, the tube 6–10 mm long, lobes 3–4 mm long, light blue to blue. Style 10–11 mm long at flowering, enclosed in the corolla, not elongating markedly as the fruits mature, the stigma usually 3-lobed. Fruits 4–5 mm long, 2.5–3.0 mm in diameter, obconic to narrowly obovoid, pendant, dehiscing by 3 basal pores. Seeds 0.6–0.9 mm long, narrowly ellipsoid. 2n=34, 56, 68, 102. June–July.

Uncommon, known only from a portion of the Jacks Fork River in Shannon County (North America, Europe, Asia). Crevices and ledges of tall, north-facing dolomite bluffs.

Steyermark (1963) considered the Missouri populations of the circumboreal C. rotundifolia to represent relicts from the Pleistocene epoch. He noted that a small set of species exists in the cool, moist microclimate in the area where the species occurs that all have their present-day main ranges to the north of Missouri and were stranded when the surrounding climate became warmer as the glaciers receded. These include Campanula rotundifolia, Galium boreale, Trautvetteria caroliniensis, and Zigadenus elegans, among others. See the introductory section on the origins of the Missouri flora in Yatskievych (1999) for further discussion.