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 bitter herbs, some species shrubby. Flowers blue to violet, in terminal or axillary bracted mostly secund spike-like racemes, or solitary or 2-3 together in the axils. Calyx campanulate, gibbous, 2- lipped, the lips entire, the upper one with a crest or protuberance upon its back and often deciduous in fruit, the lower one persistent. Corolla much exserted, recurved-ascending, dilated above into the throat, glabrous within, the limb 2-lipped; upper lip arched, entire or emarginate; lower lip spreading or deflexed, its lateral lobes small and somewhat connected with the upper, its middle lobe broad, sometimes emarginate, the margins mostly recurved. Stamens 4, didynamous, all anther-bearing, ascending under the upper lip, the upper pair somewhat the shorter, their anthers 2-celled, ciliate; anthers of the lower pair of stamens 1-celled, also ciliate. Style unequally 2-cleft at the apex; ovary deeply 4-parted. Nutlets subglobose or depressed, papillose or tuberculate, borne on a short or elongated gynobase. [Latin, a dish, from the appendage to the fruiting calyx.]
About 100 species of wide geographic distribution. Besides the following, some 15 others occur in the southern and western parts of North America, all known as Skullcap, or Helmet-flower. Type species: Scutellaria peregrlna L.
* Nutlets wingless, very slightly elevated on the short gynobase. Flowers 3"-5" long, in axillary and sometimes terminal secund racemes.
1. S. lateriflora.
Flowers 6"-15 long, in terminal often panicled racemes. Plant glabrous or very nearly so; leaves broad.
2. S. serrata.
Plants pubescent, puberulent or pilose.
Leaves all except the floral crenate or dentate, broad. Canescent, not glandular; corolla canescent.
3. S. incana.
Densely glandular-pubescent; corolla puberulent.
4. S. cordifolia.
Pubescent below, glandular above; corolla nearly glabrous.
5. S. pilosa.
Leaves all except the lowest entire, narrow.
6. S. integrifoha.
Flowers solitary in the axils or sometimes also in terminal bracted racemes. Perennial from a thick woody root.
7. S.. resinosa.
Fibrous-rooted; perennial by rootstocks or stolons. Flowers 2"-4" long. Flowers 8"-13" long.
8. S. parvula.
Minutely and densely glandular-pubescent, resiniferous.
9. S. Brittonii.
Densely cinerous-pubescent, pale.
10. S. Bushii.
Glabrous or merely slightly puberulent.
Leaves ovate, slender-petioled, cordate, obtuse.
11. S. saxatilis.
Leaves lanceolate or ovate-lanceolate, nearly sessile, acute.
12. S. galericulata.
** Nutlets membranous-winged, elevated on the slender gynobase; flowers axillary.
13. S. nervosa.
Scutellaria lateriflora L. Sp. Pl. 598. 1753.
Perennial by slender stolons, glabrous throughout or puberulent above; stem slender, leafy, erect or ascending, commonly branched, 4'-2 1/2° high. Leaves ovate, ovate-oblong or ovate-lanceolate, thin, slender-petioled, acute or acuminate at the apex, coarsely dentate-serrate, obtuse, rounded or subcordate at the base, 1'-3' long, the upper gradually smaller, the uppermost sometimes entire; racemes narrow, se-cund, axillary or often also terminal and leafy-bracted, several-many-flowered; flowers 3"-5 " long; calyx short; corolla blue, varying to nearly white, its lips about equal, one-fifth as long as the tube; nutlets borne on a very short gynobase.
In wet places, Newfoundland to Ontario and British Columbia, Florida, Mississippi, New Mexico and Oregon. July-Sept. Blue pimpernel. Side-flowering scull-cap. Madweed. Hoodwort.