COLEUS

Coleus Lour., Fl. Cochin. 372. 1970; Benth. in DC., Prodr. 12: 70. 1848; Hook. f., Fl. Brit. India 4: 624. 1885; Briquet in Engl. & Prantl. Nat. Pflanzenfam. ed. 1,4, 3 A: 359. 1897; Mukherjee, Rec. Bot. Surv. Ind. 14, 1: 51.1940; Fl. China @ eFloras.org 17: 292.

Herbs or shrubs. Leaves petiolate, margin dentate. Verticillasters 6- to many-flowered, in racemes or panicles. Bracts deciduous or absent. Flowers bisexual, zygomorphic, hypogynous, pedicellate. Calyx ovoid-campanulate to campanulate, 5-toothed or conspicuously 2-lipped, posterior tooth larger; throat glabrous or villous, fruiting calyx dilated. Corolla much exserted, erect or recurved, 2-lipped; upper lip usually 4-lobed, strongly reflexed; lower lip entire, elongated, deeply concave, navicular, narrowed at base. Stamens 4, declinate, included along with style within lower lip; filaments connate or free, rarely adnate to corolla tube; anther cells apex confluent. Style apex equally 2-cleft. Nutlets ovoid to globose, smooth, tuberculate or not.

301 species

Coleus amboinicus

Coleus amboinicus Lours., Fl Cochinch. 372. 1790; C. aromaticus Benth., Pl. Asiat. Rar. 2: 16. 1830; Plectranthus amboinicus (Lours.) Spreng., Syst. Veg. 2: 690. 1825.

Sprawling, succulent, aromatic, subligneous, perennial herb, up to 60 cm high; sometimes prostrate at base with ascending branches; branches densely spreading-hirsute, hairs up to 2.5 mm long. Leaves oppsite, simple, exstipulate, petiolate; petiole 1-2.5 cm, densely hirsute; leaf blade broadly ovate to suborbicular, 3-7(-10) cm x 3-7(-9) cm, rounded or truncate at base, apex rounded, obtuse to acute, margin coarsely crenate to dentate or serrate or entire towards base; densely pubescent or appressed-pubescent on both surfaces, gland-dotted, aromatic like oregano (Ajwain); leaves are brittle and fleshy. Inflorescence terminal racemes or panicles or spikes, 10-20 cm long, verticillasters 10-20 or more flowered, subglobose, the inflorescence axis densely pubescent. Bracts 3-4 mm long, hirsute and glandular; pedicels slender, hirsute, up to 5 mm long. Flowers bisexual, zygomorphic, hypogynous. Calyx campanulate, 1.5-4 mm long, hirsute and glandular; tube short; limb 2-lipped: upper lip erect, 1-lobed, lobe broadly ovate-oblong; lower limb of 4 lobes, lobes narrow, acute. Corolla pale blue or mauve to pink, 8-12 mm long; the tube declinate, 3-4 mm long, expanding distally, pubescent without; limb 2-lipped; upper lip 4-lobed, 4.5 mm x 3 mm, erect, puberulent; the lower lip ca. 5-6 mm x 4 mm, concave, boat-shaped. Stamens 4, filaments mostly connate into a tube around the style. Carpels 2, syncarpous, ovary superior, 4-lobed to base, lobes 1-locular, solitary ovules per loculus; style simple, slender, gynobasic; stigma equally or subequally bifid.

Fruit nutlets smooth, pale brown, ca. 0.7 mm long and 0.5 mm wide. (Fruits not observed)

Flowering and Fruiting: Plants seldom flower; Flowering observed in October and February
Common Names: Cuban Oregano, Indian Borage, Indian Mint, Mexican Mint, Mexican Oregano, Spanish Thyme; Patharchur, Patta Ajwain (Hindi)