This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Large erect simple or branched, glandular-puberulent, pubescent or glabrous, annual or perennial herbs, partly parasitic on the roots of other plants, with opposite, whorled or some alternate leaves, and large showy yellow flowers, in terminal mostly leafy-bracted racemes or panicles. Calyx campanulate or turbinate, 5-lobed, the lobes longer than or equalling the tube, sometimes foliaceous. Corolla slightly irregular, funnelform, or campanulate-funnelform, the tube villous or pubescent within, the limb spreading, 5-lobed. Stamens 4, didynamous, included, villous or pubescent; filaments slender; anthers all alike, their sacs distinct, parallel, awned at the base. Style filiform. Capsule oblong, acute, loculicidally dehiscent, longer than the calyx. [Greek, thick or hairy mouth, referring to the corolla.]
Six species, natives of eastern North America. Type species: Dasistoma aurea Raf. Plant glandular-pubescent; corolla pubescent without.
1. D pedicularia.
Puberulent, cinereous or glabrous; corolla glabrous without. Cinereous-puberulent.
Leaves entire, dentate, or some of the lower pinnatifid, firm.
Leaves entire, undulate or the lower pinnatifid, with entire lobes.
2. D. flava.
Upper leaves mostly serrate, lower pinnatifid with toothed lobes.
3. D. serrata.
Leaves, at least all but the uppermost, pinnatifid.
4. D. grandiflora.
Glabrous or very nearly so throughtout. Leaves all pinnatifid, thin.
5. D. laevigata.
Leaves entire, or the lowest dentate or incised.
6. D. virginica.
Annual or biennial, more or less glandular-pubescent, viscid, and with some longer hairs; stem rather slender, much branched, leafy, 1°- 4° high. Leaves sessile, or the lower petioled, 1-2-pinnatifid, ovate or ovate-lanceolate in outline, usually broadest at the base, 1' - 3' long, the segments incised or crenate-dentate; pedicels slender, ascending, mostly longer than the calyx, 1' - 2' long in fruit; calyx-lobes oblong, foliaceous, usually incised or pinnatifid, 3"-4" long, corolla 1' - 1 1/2' long, pubescent without, limb about 1' broad; capsule pubescent, 5"- 6" long, beak flat.
Dasystoma pectinata (Nutt.) Benth., of the Southern States, ranging north to Kentucky and Missouri, appears to be a very glandular race.
Gerardia flava L. Sp. Pl. 610. 1753.
D. aurea Raf. Journ. Phys. 89: 99. 1819.
D. pubescens Benth, in DC. Prodr. 10: 520. 1846.
Dasystoma flava Wood, Bot. & Flor. 230. 1873.
Perennial, downy, grayish; stem strict, erect, simple, or with a few nearly erect branches, 2°-4° high. Leaves oblong, lanceolate or ovate-lanceolate, usually opposite, rarely whorled in 3's, firm, entire, or the lower sinuate-dentate or sometimes pinnatifid, 3'-6' long, short-petioled, the lobes obtuse; the upper much smaller and sessile, passing into the bracts of the raceme; pedicels stout, usually shorter than the calyx even in fruit; calyx-lobes lonceolate, entire, about as long as the tube; corolla 1 1/2' - 2' long, glabrous outside, its tube much expanded above; capsule 8"-10" long, pubescent, twice as long as the calyx.
In dry woods and thickets, Maine to Ontario and Wisconsin, south to southern New York, Georgia and Mississippi. Yellow foxglove. July-Aug.