carpel. Note, also, the tendency to a dimorphic condition in some species of Flax, manifest in the different relative lengths of stamens and pistil in different individuals of the same species; a natural contrivance to favour the crossing of the flowers by insect agency.

The words line, linen, linseed, lint, and the Latin word Linum, are said to be derived from the Celtic word llin, thread. Flax has been cultivated from time immemorable for the sake of the fibre from which linen is prepared, afforded by its liber-layer. All the cloth of the ancient Egyptians left to us in their tombs is of Flax. At present, besides its cultivation to a considerable extent in Great Britain, especially in Ireland, it is largely grown in Russia, Prussia, Belgium, and the north of France. In 1877 upwards of 2,200,000 cwts. of Flax and Tow, or Codilla of Flax, were imported into the United Kingdom.

Compare, under the microscope, the Fibres of Flax with Cotton. Flax consist of long, thick-walled libercells, resembling jointed cylindrical rods. Fibres of linen from Egyptian mummies may also be compared with fibres of cotton cloth from the Peruvian tombs. (See page 135).

The seeds of the Flax plant, called Linseed, are very largely imported for the expression of the valuable "Linseed oil" which they contain. The refuse of the seeds, after the oil is expressed, is made into Linseed-cake or Oilcake," used to feed cattle. More than 1,700,000 quarters of Linseed were imported in 1877.

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13. Natural Order—Malvaceæ. The Mallow Family. DISTRIBUTION. A widely diffused Natural Order; ́most abundant in tropical and sub-tropical regions.— British genera 3, species 6.

Herbs. Flowers regular. Sepals valvate. Stamens indefinite, monadelphous.

Type--Common Mallow (Malva sylvestris).

A biennial herb, with simple alternate stipulate rotundate leaves, and axillary fascicles of regular purplish flowers.

OBSERVE the 3 bracts closely applied to the calyx, forming an involucre, sometimes called an epicalyx: the valvate æstivation of the lobes of the calyx, and imbricated (contorted) æstivation of the corolla: the slight adhesion of the petals to the stamen-tube at its base the 1-celled

anthers, an unusual condition, but characteristic of Malvaceæ.

FIG. 92.-Syncarpous fruit of Mallow, consisting of numerous carpels in a single verticel. The calyx and epicalyx are persistent.

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FIG. 93.-Embryo of Mallow, with folded cotyledons.

FIG. 94. Single sta-
men of same, with
I-celled anther.

FIG. 95.-Anther after dehiscence.

Plants of this Natural Order are destitute of noxious properties; many are mucilaginous, and the liber affords a useful fibre. The species of pre-eminent importance for textile purposes are the cotton-producing plants, belonging to the exotic genus Gossypium.

Cotton consists, not as flax of fibres of liber, but of the delicate, long, thin-walled hairs which clothe the seeds. These hairs when dry become flattened and twisted. The commercial value of Cotton depends upon the length and tenacity of these hair-cells. Lamp-oil is obtained from the seeds, and the refuse is made up into oil-cake for cattle-feeding.

In 1877 the import of raw Cotton into the United Kingdom exceeded twelve million hundred-weights; of

which upwards of eight millions were imported from the United States, and nearly one million and three-quarters from British India.

14. Natural Order-Tiliaceæ. The Lime Family.

DISTRIBUTION.-Restricted to the Tropics of both hemispheres, with comparatively few representatives in the North temperate zone. -One British genus, species I.

Trees. Leaves alternate. Sepals valvate. Stamens indefinite.

Type-Common Lime (Tilia europæa).

A large deciduous tree, with alternate obliquely cordate leaves, and peduncles adnate to leafy bracts.

OBSERVE the obliquity of the base of the leaf-blade, characteristic of the Lime. The same kind of obliquity, though usually much more decided, obtains in nearly all the species of a small, herbaceous, exotic Natural Order, in no way allied to the Limes—the Begoniaceæ―inany species of which are favourites in plant-houses from the beauty of their variegated leaves. Observe also, the bract of the Lime, adnate to the peduncle. In the axil of the leaves bearing the peduncles may be seen a small resting-bud, which grows out into a leafy branch in the following season.

Bast or Russia-matting is the liber of the Lime, torn into strips and coarsely plaited. It is principally imported from Russia. Jute is a valuable Indian fibre afforded by a species of Corchorus. It is obtained of great length and possesses a satiny lustre. In India it is used for making rice and sugar bags, called Gunny-bags.

An allied Family (not British), Byttneriaceæ, affords Cocoa, which is prepared from the seeds of Theobroma Cacao, grown in Trinidad, the northern provinces of South America, and Brazil. The seeds are contained, closely packed, in a pericarp 4 in. to 6 in. long, and 2 in, or 3 in. in diameter. They are dried, roasted,