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..
Perennial herbs, or shrubs, mostly pubescent, with entire or rarely dentate leaves, and large violet blue white or yellow flowers, solitary or clustered in the axils, or cymose in terminal panicles, or sometimes cleistogamous and inconspicuous. Calyx 5-cleft, or 5-parted, the segments narrow. Corolla funnelform or salverform, the tube usually narrow, slightly enlarged above, the limb spreading, 5-lobed, the lobes obtuse, mostly nearly equal, sinistrorsely convolute in the bud. Stamens 4, included or exserted; anther-sacs not mucronate at the base. Ovules 3-10 in each cavity of the ovary; apex of the style recurved; stigma simple, or of 2 unequal lobes. Capsule oblong or club-shaped, compressed or terete, 6-20-seeded. Seeds compressed, ovate or .orbicular, attached by their edges to the retinacula. [Named for I. Ruel or de la Ruelle, 1474-1537, an early French herbalist.]
About 200 species, mainly of tropical America, a few in Africa, Asia and Australia. Besides the following, some 6 others occur in the southern and southwestern United States. Type species: Ruellia tuberosa L.
Flowers sessile or nearly so.
Calyx-segments linear-lanceolate, scarcely exceeding the capsule.
1. R. strepens.
Calyx-segments filiform-linear, exceeding the capsule. Leaves sessile or very short-petioled.
2. R. ciliosa.
3. R. parviflora.
Flowers peduncled; peduncle with two large bracts at the summit.
4. R. pedunculata.
Ruellia strepens L. Sp. Pl. 634. 1753.
Ruellia strepens var. cleistantha A. Gray, Syn. Fl. 2: Part 1, 327. 1878.
Glabrate or somewhat pubescent; stem erect, slender, simple, or branched, 4-sided, 1°-4° high, the branches ascending. Leaves oblong, oval, or ovate, petioled, acute or subacute at the apex, narrowed at the base, 3'-6' long; petioles 2"-10" long; flowers solitary or several together in the axils.some often cleistogamous; calyx-segments linear-lanceolate, shorter than the corolla-tube, slightly pubescent or ciliate, 8"-12" long, 1/2"-1" wide; corolla blue, 1 1/2-2' long, the limb nearly as broad, the tube about as long as the throat and limb; capsule club-shaped, longer than or equalling the calyx.
In dry woods, Pennsylvania to Wisconsin, Kansas, Florida and Texas. May-July.
Ruellia ciliosa Pursh, Fl. Am. Sept. 420. 1814.
Hirsute or pubescent, at least above; stem ascending, rather stout, 1°-21/2° high. Leaves hairy, ciliate, oblong, oval, or ovate, sessile or nearly so, obtuse or subacute at the apex, narrowed at the base, 11/2'-3' long; flowers clustered or solitary in the axils, sometimes cleistogamous; calyx-segments filiform, hirsute, 10"-12" long, about i" wide; corolla blue, 11/2'-2' long, the tube equalling or longer than the obconic throat and nearly regular limb and about twice as long as the calyx; capsule shorter than the calyx.
In dry soil, southern New Jersey and Pennsylvania to Florida, west to Michigan, Kansas and Louisiana. June-Sept.
Brown, 111. Fl. Ed. 1, 3: 203. 1898. R. parviflora Britton, Man. 854. 1901.
Sparingly finely pubescent, but green; stem erect, 6'-18' tall, simple or sometimes sparingly branched. Leaves minutely pubescent, ciliolate, oblong to oblong-lanceolate, or sometimes oval, 1 1/4'-4' long, obtuse or acutish, undulate, rather acuminately narrowed at the base, manifestly petioled; flowers solitary or clustered in the axils, the pedicels very short; calyx-segments linear-filiform, bristly, 8"-12" long; corolla blue, 1 1/2'-2' long, the tube somewhat longer than the throat and somewhat exceeding the calyx, the limb 3/4'-1 1/4' broad; capsule oblong above the stipe-like base, barely 8" long.
In sandy soil, Maryland to Indiana, Florida and Texas. May-Aug.
Ruellia pedunculata Torr.; A. Gray, Syn. Fl. 2: Part 1, 326. 1878.
Finely pubescent; stem erect, 1°-2 1/2° tall, the branches spreading. Leaves ovate to oblong-lanceolate, acute or acuminate at the apex, narrowed at the base, short-petioled, the larger 2'-3' long; peduncles slender, spreading, 1'-3' long, with 2 leaflike bracts at the summit which subtend a solitary flower, or 2 or 3 slender-pedicelled ones with pedicels similarly bracted; calyx-segments awn-like, equalling the narrow corolla-tube, or snorter; corolla funnel-form, 1 1/2'-2' long; capsule about 10" long, puberulent, longer than the calyx.
In dry soil, Illinois and Missouri to Arkansas and Louisiana. June-Sept.