Thyrsacanthus
(from thyrsos, a thyrse, and Acanthus; in allusion to the form of inflorescence). Thyrse Flower. SYN. Odontonema. ORD. Acanthaceae. A genus comprising about a score species of stove, erect herbs or shrubs, natives of tropical America. Flowers red, fascicled in the axils of the bracts, pedicellate; calyx short, somewhat five-parted; corolla tube elongated; limb sub-bilabiate, four-cleft; stamens two, affixed above the middle of the tube; fascicles or cymes disposed in a thyrse. Leaves opposite, entire, often large. The species known to cultivation are described below. They thrive in a compost of about equal parts of loam and leaf soil. Propagated by cuttings, inserted, preferably in single pots, in spring, and placed in a close, warm frame. Young plants should be pinched, to encourage a bushy growth. Some of them may be cultivated in frames during the summer, but require a stove temperature in winter.
T. barlerioides (Barleria-like). fl., corolla 1in. to 1 1/2in. long, glabrous, the lobes ovate, obtuse; thyrse sub-sessile, composed of approximate whorls, 2in. to 7in. long, many-flowered, dense, interrupted at base; bracts 1/2in. long, subulate-acuminate. l. 6in. to 9in. long, 1 3/4in. to 3in. broad, sessile, shortly attenuated at apex, argutely acuminate, terminal. Stem erect, succulent. Minas Geraes. A pubescent perennial. (F. d. S. 986.) T. bracteolatus (bracteolate).* fl., corolla 1/2in. long, pubescent-viscidulous, the upper lip bifid; thyrse pubescent, terminal, narrow; bracts lanceolate-subulate; bracteoles subulate; lower peduncles three or many-flowered, upper ones one-flowered. July and August. l. oblong-lanceolate, long-acuminate, shortly petiolate, glabrous, shining, subulate, 4in. to 6in. long, 1in. to 2in. broad. Branches acutely tetragonal. h. 2ft. New Grenada, 1823. Shrub. (B. M. 4441.) T. callistachyus (beautiful-spiked).* fl., sepals pubescent, bristly-acuminate; corolla glabrous, the segments glandular within; upper lip bilobed, the lower one much deflexed; inflorescence straight, naked, the axis tomentose. July and August. l. oblong, petiolate, wrinkled, acute, below (as well as the branches) tomentose. Mexico. h. 2ft. Shrub. (L. J. F. 165; L. & P. F. G. ii. 53; R. G. 1054.) SYNS. T. lilacinus, Justicia lilacina (of gardens). T. indicus (Indian). fl., calyx deeply five-cleft, the segments erect; corolla white, with a few purple lines, funnel-shaped, the mouth oblique, the limb obscurely bilabiate, the segments spreading-reflexed; thyrse terminal. April. l. opposite, about 3in. long, oblong-lanceolate, pinnate-veined, acuminate, entire, dark green, gradually tapering at base into a short petiole. Stem and branches tetragonal. h. 2ft. Bhotan, 1857. Shrub. (B. M. 5062.) The correct name of this plant is Asystasia bengalensis.
T. Lemaireanus (Lemaire's). A synonym of T. strictus. T. lilacinus (Lilac-flowered). A synonym of T. callistachyus. T. nitidus (shining). fl., corolla 1/2in. long, slightly bilabiate; lobes drooping, sub-equal, oblong, rather blunt, about as long as the tube; fascicles somewhat distant; raceme compound at the base. l. oblong or lanceolate-oblong, acuminate, 3in. to 8in. long, tapering into the short petioles. h. 3ft. to 4ft. West Indies. Shrub. SYN. Justicia nitida (A. B. R. 570).
T. rutilans (reddish).* fl. solitary in the axils of the bracts; corolla tubular-ventricose, the lobes sub-equal, erose; raceme terminal, axillary, 8in. to 10in. long, twelve to sixteen-flowered, nodding. Winter and spring. l. sessile, oblong-lanceolate, acuminate, acute, narrowed at base, obsoletely erose denticulate on the margins, paler beneath, sparsely pilose on both sides. h. 2ft. Columbia, 1851. Shrub.
T. rutilans (reddish), of gardens. A synonym of T. Schomburgkianus. T. Schomburgkianus (Schomburgk's).* fl. brilliant crimson, distant, opposite; corolla 1in. long, with a nearly regular limb, the segments ovate, scarcely spreading; raceme terminal, elongated, long-pedunculate, glandular-pubescent. Winter and spring. l. oval-oblong, cuspidate-acuminate, 8in. to 12in. long. Branches sub-tetragonal, with smooth angles. h. 3ft. New Grenada, 1855. Shrub. (B. M. 4851.) SYN. T. rutilans (B. H. 1865, p. 97; F. d. S. 732; L. & P. F. G. iii. p. 73).
T. strictus (straight). fl. all fascicled; corolla nearly 1in. long, with an oblique, nearly regular limb, the segments oblong, acute; whorls approximate, adpressed; thyrse terminal, elongated, straight, simple, narrow, 1ft. long; bracts subulate, nearly equalling the pedicels. February and March. l. oblong, acuminate, acute at base, shortly attenuated into the petioles. Stem simple, elongated. h. 3ft. Honduras, 1840. A glabrous shrub. (B. M. 4378.) SYNS. T. Lemaireanus, Aphelandra longiscapa (of gardens), Eranthemum coccineum (F. d. S. 240), Justicia longiracemosa (of gardens), Salpingantha coccinea (of gardens).