Commelina
(named after Kaspar (1667-1731) and Johann (1629-1698) Commelin, Dutch botanists). ORD. Commelinaceoe. This genus is allied to the better known one of Tradescantia, but differs in having only three perfect stamens. Herbaceous perennials, some of which are very pretty plants, but not often seen in cultivation. The stove and greenhouse evergreen species are best grown in a light and rich soil, and are propagated chiefly by cuttings, which will root in sand, in a gentle hotbed. The tuberous-rooted species, when grown in the open, should be taken up before autumn, and stored away, like Dahlias, care being taken, however, to prevent them becoming very dry. If the position is sheltered, and the soil well drained, they may be left out. In the ensuing spring, their growth may be accelerated by the aid of slight heat, and in may, they may be transplanted out in the open. Plants thus treated, flower much stronger than seedlings.
C. africana (African). fl. of a tawny yellow colour, at first glance resembling those of some of the Papilionaceoe. May to October. l. lanceolate, creeping, rooting at the nodes. Stems slender, terete. h. 1ft. to 3ft. Cape of Good Hope, 1759. A trailing, somewhat bushy greenhouse plant. SYN. C. lutea. (B. M. 1431.) C benghalensis (Bengal). fl. blue, small. June. l. oval, green. Bengal, 1794. Stove evergreen trailer. SYN. C. prostrata. (R. G. 1868, 592.) C. coelestis (sky-blue).* fl. blue; peduncles pubescent; spathes cordate acuminate, folded together. June. l. oblong-lanceolate; sheath ciliated. h. 1 1/2ft. 1813. Half-hardy herbaceous perennial. (S. B. F. G. 3.) C. c. alba (white)* resembles the type, except in the colour of the flowers. C. deficiens variegata (deficient variegated). fl. blue, small, produced at the ends of the branches. l. ovate-lanceolate, freely and elegantly striped with longitudinal bands of white. Stems terete, branching. Brazil. A low-growing, diffuse, stove perennial. (The type is figured in B. M. 2644.) C. elliptica (elliptic).* fl., calyx white, glabrous; peduncles 2in. long, straight, with a line of reflexed hairs along the inner side. July. l. lanceolate, acuminate, flat, glabrous on both sides, shining bright green above, whitish below, seven-nerved, the middle rib prominent behind, channelled above. Stem ascending, rooting, branched, red, especially above the joints, hairy. h. 1 1/2ft. to 2ft. Lima. A very pretty greenhouse species. (B. M. 3047, under the name of C. gracilis.) C. erecta (erect). fl., spathes crowded and nearly sessile, hooded, top-shaped in fruit. Summer. l. large, 3in. to 7in. long, 1in. to 2in. wide, oblong-lanceolate, the upper surface and margins rough backwards. Stems erect, rather stout. h. 2ft. to 4ft. Pennsylvania. One of the largest species. Hardy. There is a hairy from, C. hirtella.
C. lutea (yellow). A synonym of C. africana.
C. prostrata (prostrate). A synonym of C. benghalensis. C. scabra (rough). fl. purplish-brown, terminal, eight or ten together, each blossom 1in. across. July. h. 1ft. Mexico, 1852.
C. virginica (Virginian).* fl. blue; spathes mostly solitary or scattered, peduncled, conduplicate, round-heart-shaped when expanded, pointed, in fruit somewhat hood-like. Summer. l. oblong or linear-lanceolate. Stems slender, erect, or reclined and rooting towards the base. South United States. Hardy. There is a narrow-leaved form, named C. angustifolia.