Polypòdium or Niphóbolus Lingua has coriaceous entire strap-shaped fronds, rusty tomentose beneath. It is a native of Japan and other Eastern countries.

12. GYMNOGRAMME.

This is a very large genus containing nearly one hundred species, chiefly from tropical climates. Like the last, it has naked sori, but here they are linear. The name is from yvμrós, naked, and ypapun, writing, in reference to the naked sori.

1. G. leptophylla. This is a dwarf fragile annual species with bi- or tri-pinnate tufted fronds and narrow linear pinnules. The inner fronds are on longer stipes, and more fruitful than the outer. It is a very widely distributed plant, and may be raised from spores with very little trouble.

SUB-ORDER II.-Hymenophýlleæ.

Rootstock creeping. Fronds circinnate in vernation, very delicate and almost transparent, with reticulate veins. Involucre bivalved or bilabiate. Spore-cases sessile, on a clavate or filiform receptacle surrounded with a complete oblique or transverse ring.

13. HYMENOPHYLLUM.

Fronds small, twice to four times pinnatifid or pinnate; pinnules with a midrib and no lateral veins. Sori marginal, axillary or terminal. Involucre bivalved, of the same texture as and sunk in the frond, or free. Spore-cases sessile, on a columnar receptacle within the involucre; ring oblique. There are seventy species known, chiefly from tropical and south temperate regions. The name is from vuýv, a membrane, and púλλov, a leaf, from the texture of the fronds.

1. H. Tunbridgénse.-Fronds 1 to 4 inches high, ovate, pinnate at the base, pinnatifid upwards; pinnules linear, undivided or bifid, bristly toothed. Involucre toothed. This elegant little plant grows in dense matted patches, and in habit resembles more some of the Hepática than the true Ferns. It is found in moist, shady situations in many parts of Britain, and throughout Europe from Belgium southwards, and also in the south temperate regions.

2. H. unilaterale, syn. H. Wilsoni.-This is very near the last, but it has recurved darker green more rigid pinna, and entire lips to the involucres. It has about the same range as

No. 1.

14. TRICHÓMANES.

This genus differs from the last in its cup-shaped involucre, and its long filiform receptacle. About eighty species are found in temperate and tropical countries. The derivation of the name is variously explained, but all of the explanations are open to doubt.

1. T. radicans. Fronds 6 to 12 inches high, pellucid, bior tri-pinnatifid, rachis winged. Stipes 2 to 6 inches, stout and wiry. This is very rare, and the only native species. It is found in Wales, and in a few localities in Ireland, in the vicinity of streams or waterfalls.

The members of this and the foregoing genus are not suitable for open-air culture except under quite peculiar conditions,

SUB-ORDER III.-Osmúndeæ.

Fronds coriaceous or membranous, circinnate in vernation. Spore-cases clustered in a branched panicle terminating the frond, 2-valved, opening across the apex, and furnished with a short horizontal ring.

15. OSMÚNDA.

Rhizomes tuberous, densely branched, clothed with fibres. Fronds coriaceous, tufted, once or twice pinnate. There are six species from various temperate and tropical regions, Named after a Celtic deity.

1. O. regàlis. Fern-Royal.—This is the noblest of our native Ferns, sometimes attaining a height of 10 feet. The fronds are bipinnate, branched, and fertile at the top. It is found in damp, boggy woods in this country, and is widely diffused in the north temperate zone.

O. Claytoniana, syn. O. interrupta, is a dwarf species about 18 inches or 2 feet high, clothed with a ferruginous tomentum when young, with the barren and fertile pinnæ intermixed; and O. cinnamòmea has distinct fertile and sterile fronds, the former much the smaller. Both are hardy, and natives of North America, &c.

SUB-ORDER IV.-Ophioglósseæ.

Fronds straight in vernation. Spore-cases large, 2-valved, destitute of a ring, arranged in spikes or panicles.

16. OPHIOGLOSSUM.

Rootstock with fleshy fibrous roots. Frond oblong-lanceolate, with a simple fertile spike attached to it, much in the way of the spathe and spadix of the Aroidèa. Spore-cases confluent, globose, arranged in a distichous spike. There are about four widely-distributed species. Name from opis, a snake, and yλwooa, a tongue, in allusion to the fertile spike.

1. O. vulgatum. Adder's Tongue.-This curious little plant is very distinct from all other Ferns. The single frond is from 3 to 9 inches high, with a blade from 2 to 4 inches long, and varying from ovate-oblong to lanceolate. There are two forms—vulgàtum proper, with ovate fronds and long fertile spikes; and Lusitánicum, with narrow lanceolate fronds and spikes less than an inch long. The former is not uncommon in pastures and woods, and it is also common in the temperate regions of the north and south.

17. BOTRÝCHIUM.

This genus differs from the last in its pinnate or bipinnate fronds and compound panicle of clustered spore-cases. There are six species, from temperate and tropical regions. The name is derived from Bórpus, a cluster, the form of the inflorescence.

1. B. Lunària. Moonwort.-Frond fleshy, about 4 or 6 inches high, pinnate, with lunate, crenate, or pinnatifid pinnæ. A widely distributed plant, but not so frequent in Britain as its ally the Adder's Tongue.

The remaining orders of this division are scantily, if at all, represented in gardens, except under glass. We have several native species of the Lycopodiùcece, five belonging to the genus Lycopodium, and one to Selaginella. There is also one hardy, or nearly hardy, Japanese species belonging to the latter genus, S. invólvens. It belongs to the section with dwarf rosulate flat fan-like branches. Of the Equisetaceae, the very large Horsetail, Equisetum máximum, syn. E. Telmateía, deserves mention, as it is a grand plant for introducing in damp rich soil, where it is not fully exposed to the sun. In favourable situations its barren stems rise to a height of 6 or 8 feet. The distinct manner of growth peculiar to this genus, in which the lateral branches are arranged in whorls one above the other from a sheathed jointed stem, is sufficient to entitle it to a place in the gardens of the curious,

PART II.

PRACTICAL GARDENING.

CHAPTER I.

THE CULTIVATION OF PLANTS.

THE successful cultivation of plants depends upon a great variety of conditions essential to their perfect development, such as climate, soil, and general treatment. We devote a few pages to the consideration of each of these conditions in their relation to plant life. These paragraphs are necessarily brief, but we have endeavoured to condense as much information in them as the space at our disposal will admit of; and we have confined ourselves to simple explanations or directions, as the case may be, for the use of those possessing little practical knowledge.

§ 1. VEGETABLE PHYSIOLOGY AND ECONOMY CONSIDERED IN THEIR RELATIONS TO HORTICULTURE.

A few words on the composition of the permanent fabric of plants and the principal phenomena of plant-life may serve to show the importance of exercising the utmost care and forethought in all cultural operations.

Vegetable organisms consist of every intermediate gradation between a single cell without any visible reproductive organs, up to very complex combinations and modifications of tissue and elaborate organs of reproduction in the higher stages of development. We purpose limiting our remarks to the growth, composition, and functions of the nutritive organs, or root, stem, and leaves. All plants coming within our province are built up of an infinity of cells, forming two principal kinds of tissue, namely, vascular or woody tissue, and cellular or her

baceous tissue. The cells themselves are composed of carbon, oxygen, and hydrogen, and their contents of the same elements, with the addition of nitrogen. With these essential elements several others are associated in different plants. The commoner ones are phosphorus, sulphur, silex, potash, soda, and lime. The chemical compounds of organic origin are ternary, quaternary, or even more complicated; whereas inorganic compounds generally are binary. Sugar and starch may be mentioned as the most familiar vegetable compounds. Amongst vegetable acids, citric, malic, and oxalic are the commonest. Quinine, cinchonine, and morphine are valuable alkaloid drugs. The principal phenomena of plant-life coming under our consideration are: germination, absorption, and respiration.

1. Germination.--This is the first phase in the development of independent life in a plant from a seed. In order to accomplish this stage certain conditions are indispensable. These essential conditions are: warmth, moisture, and air. The temperature at which seeds will germinate varies considerably in different species, ranging mainly from 40° to 75° Fahrenheit. But the seeds of some hardy plants will vegetate at a lower temperature, whilst a few tropical things require a still higher degree of warmth to start them into life. There must be sufficient moisture within reach of the seed to enable it to burst its coat by absorption and feed the young embryo. And the access of air is indispensable to effect the chemical changes to which the contents of the seed are subject in germination for the use of the young plant. Unless these three conditions are united in their proper degrees, the seeds will soon perish, especially if there be an excess of humidity. In the absence of moisture, and when not exposed to deleterious atmospheric or other influences, some seeds will retain their germinating powers for many years, whilst others will not grow after the first season. Most seeds contain the nourishment required for the support of the young plant in its earliest stage. This is stored up either in the embryo itself, and chiefly in the cotyledons, or it is present in the form of starch and other ingredients, in the albumen, surrounding the embryo, and constituting in many cases the bulk of the seed. When a seed is committed to the soil, it more or less rapidly absorbs sufficient water to soften its coats and distend the tissue of the embryo, causing it to push forth its radicle or rootlet, which invariably turns downwards, no matter what the position of the