Gesnera
(named after Conrad Gesner, of Zurich, 1516-1565, a famous botanist and natural historian). Including Rechsteinera. ORD. Gesneraceoe. A genus of about fifty species of very elegant stove perennials, mostly natives of Brazil; a few, however, are dispersed through Guiana, Columbia, and Peru, one extending to Mexico. Flowers disposed in opposite cymes, constituting a terminal thyrse; peduncles furnished with floral leaves or bracts at the base; corolla tube often elongated, sometimes distinctly ventricose, often, curved and gibbous at the base; limb regular, or two-lipped. Leaves opposite. The species are mostly tuberous-rooted and herbaceous.
Cultivation. Propagation is effected by the increase of tubers; also by cuttings of the shoots, inserted in peat, soon after the plants are started, and by leaf cuttings, detached and put in when they are fully matured. The flowering season of Gesneras may be considerably prolonged by starting successional batches from March until midsummer. Thorough drainage is essential, and peat and leaf soil, with the addition of a little loam and sand, forms a good compost, which should only be pressed moderately firm in potting. The bulbs may either be grown singly, in 5in. pots, or about five arranged over one 6in. in diameter; they should be covered with 1in. of soil, and kept rather dry until growth commences, when the quantity of water may be increased, according to the amount of roots. Shade from bright sunshine, in summer, is necessary, and care must be taken to keep the leaves clean, as in many species these are extremely attractive and beautifully marked. Syringing is not recommended after the leaves are developed; the water, in nearly all cases, contains lime in solution, and, as evaporation takes place, a sediment is left and retained amongst the minute hairs on the leaves of such plants as Gesneras, greatly to their disfigurement, when in flower. The plants succeed best on a moist bottom, such as a bed of coal ashes, in a house kept, in summer, at about 65deg. by night, and, in winter not below 55deg. When flowering is over, they should be gradually ripened and dried off, until all the foliage is dead, when water should be entirely withheld, and the pots stored, with their contents, in a dry part of the stove, where they may remain until starting time the following year. Thrips are frequently very troublesome on the young leaves, and should be carefully looked for and destroyed by fumigating, when in a young state. Sponging is sometimes practised, but the leaves are very brittle, and easily broken. If it can be avoided, the plants should not be placed in any house where these insects, or other pests, are present.
G. aggregata (aggregated). fl. scarlet; corolla clavate, cylindrical; peduncles axillary, one-flowered, aggregate. August. l. opposite, oblong-ovate, crenate. Branches rounded. h. 2ft. Brazil, 1816. (B. M. 2725; B. R. 329.) G. bulbosa (bulbous). fl. scarlet; cymes many-flowered, spreading from the axils of the leaves, and disposed upwards in a terminal thyrse. Summer. l. opposite, broad-ovate, cordate, serrate. Stem erect. h. 2ft. Brazil, 1816. Plant villous. (B. M. 3041.) G. chromatella (yellow). fl. rich yellow, drooping, in elegant erect spikes. Summer. l. rich dark velvety. Garden variety.
G. cinnabarina. See Naegelia cinnabarina.
G. cochlearis (spoon-leaved). fl. scarlet, in simple racemes; tube of corolla long, inflated beneath; limb five-lobed; pedicels elongated. June to August. l. opposite, on long petioles, cordate-ovate, concave, tomentose, rugose. h. 1ft. Brazil, 1837. (B. M. 3787.) G. Cooperi (Cooper's).* fl. bright scarlet, with a densely spotted throat, drooping. May. l. light green. h. 2ft. Brazil, 1829. G. discolor (two-coloured). fl. scarlet, pendulous; corolla glabrous, clavately cylindrical; pedicels elongated, slender, aggregate. June to September. l. large, opposite, petiolate, cordate-ovate, crenated, downy. h. 2ft. Brazil, 1839. (B. R. 1851, 63.) G. Donkelaariana (Donkelar's).* fl. bright vermilion, about 2in. long, freely produced in terminal heads. June. l. nearly cordate, about 8in. across, green, tinged with purple and red. h. 1ft. to 2ft. Columbia. (B. M. 5070.) G. elliptica lutea (elliptic, yellow-flowered). fl., corolla yellow; limb obliquely bilabiate; peduncles terminal, racemose and axillary, solitary. May. l. opposite, elliptic, wrinkled, serrate; lower ones petiolate, upper ones sessile. h. 1ft. Santa Martha, 1844. (B. M. 4242.) G. exoniensis (Exeter).* fl. deep orange-scarlet, with a yellow throat, numerously produced in closely-set masses, about 1ft. through. Winter. l. dark rich velvety, covered with minute red hairs. Garden hybrid. G. glaucophylla (glaucous-leaved). fl. deep orange-red; throat light, spotted with orange. Summer. l. glaucous, prettily mottled, covered with red hairs. G. Hondensis (Honda). fl. yellowish-red, hairy, ventricose at top; peduncles axillary, one-flowered, by twos and threes. May. l. opposite, somewhat obliquely ovate-oblong, crenulated, woolly beneath. h. 1ft. Brazil, 1845. (B. M. 4217.) G. Lindleyana (Lindley's). fl. freely produced; upper part of tube rosy-pink; lower part and limb yellow, freckled with red. July. l. broadly ovate, rich deep velvety-green and red. Brazil, 1825.
G. Marchii (March's). A synonym of G. pendulina.
G. naegelioides (Naegelia-like).* fl. bright rosy-pink, marbled with red, large, tubular; throat yellow, dotted with red. Summer. l. cordate-ovate, deep green, hairy on the margins and roughly toothed. An elegant garden hybrid, with numerous varieties, of which the following are a selection: G. n. aureo-roseum (golden-rose). fl. bright rosy-lilac; upper portions of the limb plain rose-colour, lower part beautifully spotted with carmine; throat marked with orange-yellow. l. ovate-acuminate.
G. n. bicolor (two-coloured). fl., upper half rosy-red, lower orange-yellow; limb and throat orange-yellow, profusely spotted with red. l. ovate-lanceolate, serrated, purplish-red on the under side, bluish metallic-green on the upper.
G. n. candida (white). fl. pure white, marked with pale yellow in the throat, tubular; produced in great profusion. l. broadly-ovate, toothed, deep green. Stems erect, branching.
G. n. corallina (coral-red). fl. rich deep red, almost maroon; throat orange-yellow, profusely spotted with red. l. deep green, coarsely toothed. Stems red.
G. n. lilacinella (lilac). fl. delicate lilac-colour, beautifully marbled with a deeper tint of the same colour; throat lemon-colour; produced in profusion upon the numerous laterals, and from the base of the leaves upon the main stem, upon long foot-stalks. l. large, cordate, coarsely toothed, deep bright green above, paler and woolly below.
G. n. scintillans (glistening). fl., outside deep plum-colour; limb rosy-red; throat orange-yellow, streaked and dotted crimson, about 2in. long in the tube, and nearly as much across the limb; produced in large lateral heads towards the tops of the shoots. l. somewhat oblong, serrated, bright green above, pale below, tinged with red.
G. nigrescens (blackish). fl., tubes dark red; throat light orange, spotted. l. large, dark velvety. Garden hybrid.
G. pendulina (pendulous). fl. scarlet, numerous, in whorls; corolla drooping, cylindrical, gibbous at top; limb five-lobed. August. l. three in a whorl, petiolate, ovate, crenate. h. 3ft. Mexico, 1844. SYN. G. Marchii (under which name it is figured in B. M. 3744).
G. purpurea (purple). fl. purple; panicle sub-verticillate; corolla with a long tube; upper lip straight, two-lobed. June to September. l. whorled, cordate-oblong, toothed, downy. h. 2ft. Brazil, 1849. G. pyramidalis (pyramidal).* fl. deep orange-red; throat and lip light orange, spotted. Winter. l. 7in. broad, nearly round, with a dark velvety ground. Garden hybrid.
G. refulgens (refulgent). fl. rich deep red. Summer. l. cordate-ovate, clothed with short blood-coloured hairs. h. 1ft. to 1 1/2ft. A beautiful plant, of garden origin.
G. tuberosa (tuberous-rooted). fl. scarlet; peduncles from base of rhizome. August. l. broad-ovate, toothed, cordate at base, downy. Stem on horizontal rhizome. h. 6in. Brazil, 1834. (B. M. 3664.) G. zebrina. See Naegelia zebrina.