Part 58

=B. serrulatum= (saw-edged).* _cau._ elongated, stout, ascending. _sti._ 6in. to 12in. long, strong, erect, smooth, nearly naked. _fronds_ oblong-acuminate, 1ft. to 2ft. long, 6in. to 9in. broad, with twelve to twenty-four pairs of quite distinct articulated linear oblong pinnæ on each side, which are about 4in. to 5in. long, 1/2in. broad, narrowed gradually towards the point, and downwards to a narrow base, the margins finely incised. Florida, &c., 1819. Stove or greenhouse. SYN. _B. striatum_. (H. S. F. 3, 159.)

=B. striatum= (striped). A synonym of _B. serrulatum_.

=B. unilaterale= (one-sided).* _cau._ elongated, densely scaly at the crown. _sti._ slender, erect, 1in. to 4in. long, slightly scaly below. _fronds_ lanceolate, 6in. to 12in. long, 1-1/2in. to 2in. broad; pinnæ numerous, spreading horizontally, linear, 3/4in. to 1in. long, central ones 1/4in. to 3/8in. broad, point usually mucronate; edge entire, or nearly so, the lower part dilated to a broad base. _sori_ in a line close to the midrib. Tropical America, 1829. Widely distributed. Stove or greenhouse species. SYN. _B. polypodioides_, under which name it is usually found in gardens.

=BLECHUM= (a Greek name for an unknown plant, supposed to resemble Marjoram). ORD. _Acanthaceæ_. Stove herbaceous perennials. For culture, &c., _see_ =Justicia=.

=B. Brownei= (Browne's). _fl._ white, in a dense bracteated spike, which is four-cornered; bracts ovate, downy. Summer. _l._ ovate elliptical, somewhat toothed. _h._ 2ft. West Indies, 1780. The other species introduced are: _angustifolium_, blue; _braziliense_, blue; and _laxiflorum_, white.

=BLEPHARIS= (from _blepharis_, the eyelash; in reference to the fringed bracts of the calyx). ORD. _Acanthaceæ_. Dwarf shrubs or herbs, often spiny and woody, allied to _Acanthus_. Flowers in bracteate spikes; calyx cruciately four-parted, bracteate; upper segment entire, three-nerved; lower, two-nerved; corolla-tube very short; lip five-lobed, three lobes often much larger than the others; stamens four, sub-didynamous. For culture, &c., _see_ =Acanthus=.

=B. boerhaaviæfolia= (Boerhaavia-leaved). _fl._ blue. July. _l._ usually four in a whorl, elliptic, toothed. _h._ 1ft. India, 1829. Stove annual.

=B. capensis= (Cape Colony).* _fl._ blue. July. _l._ narrow, lanceolate, spinose. _h._ 1ft. Cape of Good Hope, 1816. Greenhouse biennial.

=B. furcata= (forked-spined). _fl._ blue. July. _l._ lanceolate, entire or spiny; bracts large, strongly spinose. _h._ 2ft. Cape of Good Hope, 1846. Greenhouse evergreen shrub.

=B. linearifolia= (narrow-leaved). _fl._ blue. July. _l._ long, entire, linear, glabrous or hairy, not spiny. _h._ 2ft. Guinea, 1823. Stove annual.

=B. procumbens= (trailing).* _fl._ blue. July. _l._ linear lanceolate, spiny. _h._ 1ft. Cape of Good Hope, 1825. Greenhouse evergreen trailer.

=BLEPHILIA= (from _blepharis_, the eyelash; in allusion to the ciliated bracts). ORD. _Labiatæ_. Ornamental hardy perennials, closely allied to _Monarda_, but differing from it in the calyx tube having thirteen instead of fifteen nerves, and being naked in the throat, while the corollas are much smaller and more dilated. They are of easy culture in ordinary soil. Increased readily by dividing the roots in early spring.

=B. ciliata= (ciliated). _fl._ blue; whorls all distinct; bracts ciliated, reddish at top. July. _l._ almost sessile, ovate-oblong, narrowed at the base, canescent beneath. _h._ 1ft. to 2ft. North America, 1798.

=B. hirsuta= (hairy). _fl._ purple or blue; whorls more numerous than in the preceding; upper ones approximate. July. _l._ petiolate, ovate, roundly cordate at the base, hairy on both surfaces. _h._ 1ft. to 2ft. Virginia, 1798. Habit more branched and loose than in _B. ciliata_.

=BLESSED THISTLE.= _See_ =Cnicus benedictus=, properly =Carbenia benedicta=.

=BLETIA= (in honour of Don Louis Blet, a Spanish botanist). ORD. _Orchideæ_. A large genus of, for the most part, stove terrestrial orchids. Flowers purple or whitish, in terminal racemes. Leaves narrow, grass-like. Pseudo-bulbs round, flattened. The flowers are freely produced when the plants are thoroughly established, and are valuable for bouquets, as well for their pleasing colour as for the time they last in perfection. Bletias thrive best in a compost of loam and leaf mould. About 2in. of crocks, covered with a layer of moss, should be placed in the bottom of the pot, which should be filled to within 1in. of the top with soil. The bulbs should then be inserted, and just covered. A good supply of water during the growing season is necessary, and only a moderate amount of heat. After growth has ceased, a period of rest is required, during which time very little water should be given. Propagation is effected by divisions, which should be made after the plants have finished flowering, or previous to their starting into growth.

=B. campanulata= (bell-shaped). _fl._ deep purple, with a white centre, lasting a considerable time in perfection. Mexico.

=B. florida= (florid).* _fl._ pale rose-coloured; lip not spurred. July and August. _h._ 2ft. West Indies, 1786. A very pretty species. (B. R. 1401.)

=B. gracilis= (slender). _fl._ pale greenish-white; sepals and petals nearly equal, lanceolate, acuminate; lip red and yellow; scape simple. _l._ oblong, lanceolate, plicate. _h._ 1-1/2in. Mexico, 1830. (B. R. 1681.)

=B. hyacinthina= (Hyacinth-like).* _fl._ purple, racemose; lip not spurred, beardless; scape about as long as the leaves. March to June. _l._ lanceolate. _h._ 1ft. China, 1802. This pretty species has proved to be quite hardy. (Garden, Nov., 1879.)

=B. patula= (spreading-flowered). _fl._ purple, spreading; scape tall, branched. March. _l._ lanceolate. _h._ 2ft. Hayti, 1830. (B. M., 3518.)

=B. Shepherdii= (Shepherd's).* _fl._ on branching spikes, purple, marked down the centre of the lip with yellow. Winter. _l._ long, lanceolate, dark green. Jamaica, 1825. (B. M. 3319.)

=B. Sherrattiana= (Sherratt's).* _fl._ about a dozen on a spike, rich rosy purple; petals very broad, twice the breadth of the sepals; lip deep purple in front, marked with white and yellow down the centre. _l._ three to four-plicate. Pseudo-bulbs depressed. New Grenada, 1867. (B. M. 5646.)

=B. verecunda= (modest). _fl._ purple; lip not spurred. January. _h._ 3ft. West Indies, Mexico, &c., 1733. (B. M. 930.)

=BLIGHIA SAPIDA.= The Akee Tree. This is now included under the genus =Cupania= (which _see_).

=BLIGHT=, or =BLAST=. Applied to various diseases of plants which are caused or accelerated either by the presence of parasitic fungi or insects, or by atmospheric influence. Blight generally proves fatal to the whole or part of the subject attacked.

=BLIND.= A term applied to plants which fail to produce central buds. The defect is frequently noticeable in the Cabbage, and other plants of the _Brassica_ tribe; and is, perhaps, mainly due to the attacks of insects in a very early stage. Great care should therefore be exercised in keeping the seed beds clear of insect pests, by the application of ashes, lime, and soot, or spent hops.

=BLOOD FLOWER.= _See_ =Hæmanthus=.

=BLOODROOT.= _See_ =Sanguinaria canadensis=.

=BLOOM.= A fine powder-like substance found on Grapes, Cucumbers, Plums, &c., and varying in colour in the different subjects. It should be carefully protected, as it improves the appearance of the fruit. The term is also generally used-—although incorrectly-—as the plural of blossom.

=BLOSSOM.= The flower of a plant, or the essential organs of reproduction, with their appendages.

=BLUE-BELLS.= _See_ =Campanula rotundifolia= and =Scilla nutans=.

=BLUE-BOTTLE.= _See_ =Centaurea Cyanus=.

=BLUE GUM TREE.= _See_ =Eucalyptus globulus=.

=BLUETS.= The French name for _Centaurea Cyanus_. _See also_ =Houstonia cœrulea= and =Vaccinium angustifolium=.

=BLUMENBACHIA= (in honour of John Frederick Blumenbach, M.D., Professor of Medicine at Göttingen, and distinguished as a comparative anatomist). ORD. _Loasaceæ_. Elegant branched, climbing or trailing, annual, biennial, or perennial herbs, generally covered with stinging hairs, which are very objectionable. Flowers axillary, solitary, bracteate, very pretty and interesting. Leaves opposite, lobed. They are of easy culture in ordinary garden soil. Propagated by seeds, which should be sown in pots, in spring, and placed in a gentle heat, where they will germinate in about a fortnight. When the seedlings are large enough, and after having been previously hardened off, they may be planted out in their blooming quarters, or potted on and trained to a trellis.

=B. chuquitensis= (Chuquitan).* _fl._ solitary, axillary, with five to ten boat-shaped red petals, which are yellow within. September. _l._ oblong-lanceolate, pinnate; segments pinnatifidly lobed. Peru, 1863. Half-hardy climbing perennial. See Fig. 257. (B. M. 6143.)

=B. contorta= (twisted).* _fl._ orange-red, with cup-shaped green scales within. July. _l._ oblong-ovate, pinnatifid; lobes incisely toothed. Peru. Greenhouse climber, but may be grown against a wall, out of doors, during the summer. (B. M. 6134.)

=B. coronata= (crowned).* _fl._ of pure glossy whiteness, quadrangular, crown-shaped, 2in. in diameter each way. June. _l._ narrow, bipinnatifid, cut into small segments. _h._ 1-1/2ft. Chili, 1872. This is an elegant dwarf, tufted, erect biennial, with the pure white blooms imbedded in the metallic lustrous foliage. SYN. _Caiophora coronata_. See Fig. 258.

=B. insignis= (remarkable).* _fl._ with whitish petals and reddish-yellow scales, axillary, on long peduncles, about 1in. in diameter. July. _l._, lower ones five to seven-lobed; upper ones deeply bipinnatifid. _h._ 1ft. Chili, 1826. Hardy annual trailer. SYN. _Loasa palmata_. (B. M. 2865.)

=BOBARTIA= (named after Jacob Bobart, Professor of Botany at Oxford in the seventeenth century). ORD. _Irideæ_. A small genus of greenhouse or hardy bulbous plants, closely allied to _Sisyrinchium_. The species in cultivation are very pretty hardy plants, but require protection from severe frosts and excessive rains. They thrive best in a warm, light soil, and make pretty plants for rockwork. Propagated by separating the offsets during autumn. This genus has been much misunderstood. Among the plants which have been referred to it are some which now find places in the genera _Aristea_, _Sisyrinchium_, _Homeria_, _Marica_, _Moræa_, &c., &c.

=B. aurantiaca.= _See_ =Homeria aurantiaca=.

=B. gladiata= (sword-shaped). _fl._ yellow, thinly sprinkled with purple dots near the centre, handsome, nearly 2in. across. _l._ linear, ensiform, narrow, slightly glaucous, 1ft. or more in length. 1817. SYN. _Marica gladiata_. (B. R. 229.)

=B. spathacea= (rush-like). _l._ rush-like, several feet in length; flower-stem as long as leaves, bearing near extremity a cluster of pale yellow flowers, with narrow segments. Each flower lasts but one day; as a good many, however, are developed in each spathe, there is a succession which lasts some time. 1832. SYN. _Xyris altissima_. (L. B. C. 1900.)

=BOCCONIA= (named after Paolo Bocconi, M.D., a Sicilian botanist, author of the "Museum des Plantes," and "Histoire Naturelle de l'Ile de Corse," &c.). ORD. _Papaveraceæ_. Two of the species are greenhouse or half-hardy shrubs. Flowers inconspicuous, in terminal panicles, with the branches and branchlets each furnished with one bract. Leaves stalked, glaucous, large, lobed. This genus does not well agree with the rest of _Papaveraceæ_, from its having one-seeded capsules and apetalous flowers. _B. cordata_ is a handsome, hardy, herbaceous plant, with a stately habit and finely-cut foliage, and, where bold subjects are desired, few will be found superior to it. As an isolated specimen on the lawn, or by frequented walks, where it will not be too closely surrounded by tall plants, it may be grown with marked effect. It also forms a good subject for pot culture, and is largely used for sub-tropical bedding. The soil most suitable for its culture is a good fat loam, of considerable depth. Propagated by cuttings, taken from the axils of the larger leaves, during early summer; or by young suckers, taken from established plants, during summer, as they will then flower the following season. If the former method is employed, the cuttings should be pushed on, so that there are plenty of roots before the winter sets in. The other two species require greenhouse culture; but both are eminently suited for sub-tropical gardening, in any light rich soil, or well-drained and airy situation. They are best propagated by seeds, sown in a hotbed in spring, the seedlings being placed out from June to September.

=B. cordata= (cordate).* _fl._ buff-coloured, very numerous, borne in very large terminal panicles; individually they are not showy, but the fully grown inflorescence has a very distinct and pleasing appearance. Summer. _l._ large, reflexed, deeply-veined, roundish-cordate; margins lobed or sinuated. Stems growing rather close together, thickly set with leaves. _h._ 5ft. to 8ft. China, 1795, and 1866. Mr. Robinson recommends its being grown in the angle of two walls which shelter it from the north and east. It runs quickly at the roots, and the suckers may be cut off to the benefit of the parent plant; each sucker will form a strong plant in a year's time. SYNS. _B. japonica_ and _Macleaya yedoënsis_. See Fig. 259. (B. M. 1905.)

=B. frutescens= (shrubby).* _fl._ greenish. October. _l._ large, sea-green, oval-oblong, cuneated at the base, pinnatifid. _h._ 3ft. to 6ft. Mexico, 1739. (L. B. C. 83.)

=B. integrifolia= (entire-leaved). _fl._ greenish; panicle crowded. _l._ flat, oblong, tapering towards each end, entire, or scarcely crenated. _h._ 9ft. Peru, 1822.

=B. japonica= (Japanese). Synonymous with _B. cordata_.

=BœBERA= (named after Bœber, a Russian botanist). ORD. _Compositæ_. A genus of evergreen greenhouse shrubs, now generally referred to _Dysodia_. They are of easy culture, thriving in ordinary garden soil. Propagated by cuttings, made of young, rather firm, shoots, and placed in sand, under a glass. There are several other species besides the one given below, but they are not of much horticultural value.

=B. incana= (hoary).* _fl.-heads_ golden; peduncles one-headed. November. _l._ pinnate, rather hairy; leaflets linear acute, channelled, some entire, and some trifid. Stem hairy. _h._ 1-1/2ft. Mexico, 1828. (B. R. 1602.)

=BœHMERIA= (named after George Rudolph Bœhmer, a German botanist). ORD. _Urticaceæ_. A genus of shrubs or herbaceous plants, allied to _Urtica_, from which it is distinguished in not having stinging hairs. _B. nivea_ is the only species having any horticultural value. This thrives best in a warm, sandy soil; and is increased by divisions.

=B. nivea= (snowy). _fl._ greenish, disposed in spikes. _l._ broadly cordate, about 6in. long by 4in. broad, terminating in a long slender point; edges serrate, covered on the under side with a dense coating of white down. _h._ 3ft. to 4ft. China. A shrub-like perennial, rather more curious than beautiful.

=BOG BEAN.= _See_ =Menyanthes trifoliata=.

=BOG-EARTH.= _See_ =Peat=.

=BOILERS.= These are very important articles in all gardens where there are glass houses, and the best should always be selected. They are made in cast and wrought iron, both of which have their special advantages and disadvantages. The former are less liable to burn through when encrusted with any deposit from the water, but will crack with sudden changes of temperature, by reason of the granular form of the metal not allowing gradual contraction; the latter may burn through where there is any deposit of mud or other matter, but they will not crack, and will stand a greater pressure than those made of cast metal. It is, however, the better plan to use Boilers of wrought iron, as, with careful usage, they are less liable to break down in hard frosts than are the others. As the value of the plants, as well as that of the Boiler, has to be considered, should such a contingency occur, it is certainly advisable to reduce all risks to a minimum; and as the average life of a Boiler is from ten to fifteen years, a slightly larger first cost is not of very serious moment. The forms of Boilers are very diverse, and, in some of the patented forms, complicated. But, whatever the shape, the following points are essential: A clear and unrestricted waterway of not less than 2in. in thickness; the greatest exposure of surface to the direct action of the fire; a sufficient fire space; and a fire-bar area calculated to supply enough fresh air to the fire to support thorough combustion. The forms generally used for horticultural work are the following, or some modifications of them; and, however grand the name, their chief value consists in the attested heating capacity at a given cost: The Saddle Boiler, which is made of various sizes, with or without check ends, cross tubes, and other devices for increasing the heating surface, and also of a tubular form; the Upright Cylinder (a vertical section of which is shown in Fig. 260); the Upright Tubular Cylinder; the Horizontal Tubular; and the Cornish or Horizontal Cylinder. Combinations of the various forms, and complicated patterns of different kinds, are made for particular purposes; but in no case should large Boilers be used, unless they are recommended, by one competent to judge, as suitable for the purpose they are needed to fulfil. In every case, it is necessary that the Boiler should be fixed in a proper manner. It is also good policy to have Boilers about 30, or even 50 per cent., more powerful than is actually required, when they are new, as, from various causes, their heating power falls off in a year or two in many places; and, under ordinary work, it is not desirable to stimulate the action in order to command sufficient heat. There is no doubt that, for general purposes, some modification of the Saddle or Cylinder Boiler is by far the best, all things duly considered; but it is impossible to give any practical advice without a thorough knowledge of the requirements of any particular place. Gas Boilers are also useful for small places. These are made in many forms, and are, as a rule, in the shape of a cylinder, with a coned inside, against which the flames play. Some Gas Boilers have also a superheater attached; this exhausts the heat from the air which has passed through the Boiler. Another good form is made of horizontal tubes, which contain the water, the flames playing over and amongst them. An atmospheric burner of approved construction should be used where gas is the heating power. A sufficient supply of gas should be assured by using supply pipes of a good size. Care should be taken to keep these pipes free from water, and protected from frost by silicate cotton lagging, or some other good non-conductor. Except for very small places, however, gas apparatus is almost useless, and will never supersede fuel Boilers. For other particulars regarding Boilers, _see_ =Heating= and =Stoking=.

=BOIS-PERDRIX.= _See_ =Heisteria=.

=BOLBOPHYLLUM.= _See_ =Bulbophyllum=.

=BOLETUS= (from _bolos_, a mass; in reference to its massy or globular form). ORD. _Fungi_. The only species of this rather large genus demanding mention is _B. edulis_ (see Fig. 261), which is considered an excellent article of food. It is easily distinguished, and is often of large size and somewhat unshapely; the pileus is usually of a dusky yellow or brownish hue, but sometimes brighter and more of a chestnut colour; the flesh is white, and does not change to a blue colour when cut (this is a very important characteristic, and should always be noticed). It is a species common in most districts, usually growing in woods, and appearing chiefly in the autumn.

=BOLEUM= (from _bolos_, a ball; in reference to the shape of the seed-pods). ORD. _Cruciferæ_. An ornamental, hardy, evergreen shrub, well adapted for rockwork, in ordinary soil. It requires slight protection in winter if planted in very exposed situations. Propagated by seed, sown in a pot, in spring, and placed in a frame, or in the open border during summer.

=B. asperum= (rough).* _fl._ cream-coloured; racemes erect, elongated; pedicels very short, the lower ones bracteate. April. _l._ alternate, oblong, linear; lower ones somewhat divided. A suffruticose, erect, branched plant, hispid from stiff hairs. _h._ 6in. to 1ft. France. 1818.

=BOLLEA.= _See_ =Zygopetalum=.

=BOLTED.= A term used in reference to plants that have prematurely run to seed.

=BOLTONIA= (named after J. B. Bolton, an English professor of botany). ORD. _Compositæ_. A genus of rather pretty hardy herbaceous perennials. Flower-heads with white or purplish rays. Leaves pale green, lanceolate, sessile. They thrive in common garden soil. Propagated by divisions of the roots, in March.

=B. asteroides= (Aster-like).* _fl.-heads_ flesh-coloured, stellate, disposed in a rather large terminal panicle. August. _l._ all entire, somewhat broadly lanceolate, narrowed at both ends. _h._ 2ft. North America, 1758. (B. M. 2554.)

=B. glastifolia= (woad-leaved).* _fl.-heads_ pink. September. _l._, lower ones serrated. _h._ 1-1/2ft. North America, 1758. (B. M. 2381.)

=BOMAREA= (derivation of name doubtful). ORD. _Amaryllidaceæ_. A genus of handsome half-hardy twiners, closely allied to _Alströmeria_, from which it is chiefly distinguished by its twining habit and some difference in the capsule. They are of comparatively easy culture, thriving in a compost of peat, leaf mould, loam, and sand, with good drainage. Manure water should be given during the season of growth. Although they make fine pot plants, their full beauty is only developed when planted out in the conservatory or greenhouse border. Propagated by seeds, or by careful divisions of the underground stem. In making a division, it is necessary to observe that the part taken has some roots by which to live till new ones are formed. It should be potted at first, and may, when established, be planted out or shifted on. Seeds may be raised in a warm house without difficulty. They germinate in a few weeks; and when the young plants are 2in. or 3in. high, they should be placed separately in small pots, shifting them on as necessary, or planting them out. In favoured southern localities, several species have proved hardy, but they are much the best when grown in a greenhouse.

=B. acutifolia Ehrenbergiana= (Ehrenberg's acute-leaved). _fl._ undulate, outer segments deep orange, the inner ones paler and spotted. Spring. _l._ lanceolate acute, smooth. Mexico, 1878. (B. M. 6444).

=B. Caldasiana= (Caldas's).* _fl._ orange yellow, spotted crimson. _l._ ovate-lanceolate, acute. Peruvian Andes, 1863.