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..
Annual or perennial low mostly branched herbs, parasitic on other plants, with opposite dentate or incised leaves, and small blue purplish yellow or white often variegated flowers in terminal leafy-bracted spikes. Calyx not bracteolate at the base, campanulate or tubular, 4-cleft (rarely 5-cleft with one of the lobes much smaller than the others). Corolla very irregular, 2-lipped, the upper lip erect, scarcely concave, 2-lobed, its margins recurved; lower lip larger, 3- lobed, spreading, its lobes either emarginate or obtuse. Stamens 4, didynamous, ascending under the upper lip of the corolla; anther-sacs equal and parallel, mucronate at the base. Capsule oblong, loculicidally dehiscent, many-seeded. Seeds oblong, longitudinally ribbed. [Greek, delight]
About no species, natives of temperate and cold regions of both the northern and southern hemispheres. Besides the following, another occurs in northwestern North America. Type species: Euphrasia officinalis L.
Flowers 2 1/2"- 4" long.
Leaves markedly pubescent on both sides.
1. E. arctica.
Leaves glabrate or sparingly pubescent.
2. E. americana.
Flowers 1 1/2"- 2" long.
Stem 3'-20' long; flowers racemose-spicate.
3. E. Randii.
Stem 1'-2' high; flowers subcapitate.
4. E. Oakesii.
Euphrasia arctica Lange, Bot. Tidskr. 4: 47. 1870.
Annual; stem erect, simple, or with a few erect branches from near the base, pubescent with crisped hairs, 2-7' high. Leaves ovate to obovate, obtuse, pubescent on both sides, 2-5-toothed on each margin, the teeth sharp or blunt; spike 1'- 4' long, the bracts imbricated, at least above, broadly oval to orbicular, cuneate at the base, sharply toothed, glandular-pubescent beneath or also on the margins; calyx-teeth acute; corolla 3"-4" long, lilac, or variegated, the lobes of its lower lip nearly parallel; capsule oblong-elliptic, ciliate on the margins, and more or less pubescent or pilose, about as long as the calyx.
Bluffs and slopes, Greenland to Hudson Bay, New Brunswick, Maine and Minnesota. Has been erroneously referred to E. hirtella Jordan. Summer.
Euphrasia americana Wettst. Mon. Euph. 127. 1896. E. canadensis Townsend, Journ. Bot. 36: 1. 1898.
Annual, stem pubescent with crisped hairs, often at length much branched, 4'-10' high. Leaves glabrous, or sparingly pubescent, ovate to oval, obtuse or acutish at the apex, 3-5-toothed on each side, 3"-6" long, 1 1/2"- 4 1/2" wide, the teeth acute; bracts cuneate or obtuse at the base, dentate, pubescent, not glandular, slightly shorter than the flowers; calyx-teeth lanceolate, acuminate; corolla 3"- 4" long, purplish or nearly white, the somewhat spreading lobes of its lower lip emarginate; capsule narrow, cuneate, 2"-3" high, about equalling the calyx.
In fields and on hills, Maine and New Hampshire to New Rrunswick and Newfoundland. Summer.
Euphrasia officinalis L. is not known from North America.
Euphrasia Randii Robinson, Rhodora 3: 273. 1901.
E. Randii var. (?) Farlowii Robinson, loc. cit. 274. 1901.
Annual; stem simple or branched, erect or decumbent, 3'-2o' long, purplish, covered with whitish hairs. Leaves ovate to suborbicular or fan-shaped, finely pubescent on both sides, 4-6-toothed on each margin, the teeth obtuse or acutish; flowers spicate-racemose; calyx pubescent, its teeth triangular-lanceolate; corolla about 2" long, violet to nearly white, with a yellow eye; capsule oblong-elliptic, ciliate, notched.
Thickets and grassy places, Newfoundland to Quebec and Maine. July-Aug.
Euphrasia Oakesn Wettst. Mon. Euph. 142. 1896.
Stem erect or ascending, very slender or filiform, simple, 1'-2' high, somewhat pubescent. Stem leaves 2 or 3 pairs. Bracts and leaves orbicular or broadly oval, narrowed or nearly truncate at the base. 2"-3" long, obtuse, pubescent, not glandular, with 2-5 blunt teeth on each side; spike short, capitate, only 3"-s" long, the bracts densely imbricated; calyx-teeth triangular-lanceolate, short; corolla l1/2"-2" long, purplish-white with a yellow eye; capsule oblong-elliptic, ciliate, longer than the calyx.
White Mountains of New Hampshire and on Mt. Katahdin, Maine. July-Aug.