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Plectranthus (Greek, spur flower; alluding to the swollen base of the corolla-tube). Labiatae. Herbs and subshrubs, bearing rather small flowers ranging from blue and purple to lilac; sometimes planted for ornament in warm countries.
Inflorescence various; calyx 5-toothed, the teeth equal or variously 2-lipped; corolla-tube exserted, swo behind at the base; limb 2-lipped; stamens 4, filam toothless, free: nutlets ovoid or oblong, smooth minutely punctulate.—About 120 species from tropical and subtropical regions of Afr. and Asia, Japan, Austral., and Polynesia. The genus is cloallied to Coleus, being distinguished by having stamens free instead of united at the base into at which is distinct from the corolla. In other respects genus has wide limits of variation. Sometimes ca cockspur-flower. Prop, by cuttings which root easier.
P. albocaeruleus, N. E. Br. A tall branched herb with br - ovate lvs. 2-4 in. long racemes crowded, spike-like; corolla and bluish. Trop. Afr.—P. chiradzulensis, Baker. About 3 ft. high, with alender branchéa: lvs. petioled, toothed not unlike those of the common nettle: fls. in terminal loose panicles 6 in. long, long- lipped and light blue; fls. in winter. Trop. Afr.—P. ciliatus, E. Mey. St. covered with purple hairs: lvs. broad, bright green above, purple-red beneath: fls. white with purple spots. S. Afr. Intro, into Italy.—Said to be a showy autumn- and winter-flowering plant with a compact habit.—P. Coppinii, Neck. A quick-growing species with root-tubers and also aerial ones produced in the axils of the branch-nodes. Trop. Afr. This species is cult, and the produce sold for food in the Soudan.—P. crassus, N. E. Br. A stout subshrub, covered with velvety hairs: lvs. ovate, 3-6 in. long, short- petioled, crenate, upper surface rich velvety green, under surface gray with prominent reticulate venation : fls. in stout erect terminal panicles 1 ft. or more long, purple-blue. Trop. Afr. B.M. 8030. Gn. 73, p. 629.—P. Mahonii, N. E. Br. Sts. 3 ft. high: lvs. ovate, 3-4 in. long, petiolate, the lower cuneate, the upper cordate at the base, toothed: racemes 3-8 in. long, loosely many-fld.; fls. rather small, violet-blue. Trop. Afr. B.M.7818.—P. saccatus, Benth. Subshrubby and rather succulent, with horizontally spreading branches about 1 ft. long: lvs. 2-3 in. long, ovate, coarsely toothed: racemes erect, simple, lax-fld.; corolla large, pale blue. Natal. B.M . 7841. Intro, into English botanic gardens and said to be a very ornamental species with probably the largest fls. of the genus.
F. Tracy Hubbard
The above text is from the Standard Cyclopedia of Horticulture. It may be out of date, but still contains valuable and interesting information which can be incorporated into the remainder of the article. Click on "Collapse" in the header to hide this text.
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