joints, and the offshoots of the Couch-grass are but young underground stems. We always hear "bulbous roots" spoken of, and these again are not real roots, but contracted stems and leaf-buds. We call them corms (E). If the corm of a Crocus be cut in two just before the leaves begin to appear, it will be found to consist of a collar from which the true roots

F

Fig. 9.

spring, a solid white part which is the stem, and one or two little buds in the upper parts, which contain the germs of leaves and flowers. The old corm wastes away when it has done flowering, and a new corm is formed beside it. In the Crocus the new corm forms above the old one, and the remains of the old one hang like a fibrous ring at the base of the new.

H

Fig. 10.

The first action of a germinating seed is to send down a taproot; as the plant increases in size this generally disappears, and the root assumes the characteristic form of the species. Herbaceous plants have generally either fibrous roots, the fibres extending perpendicularly or horizontally, as the case may be ; or thickened roots, in which a store of mucilage is laid up

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for the use of the plants. The spindle-shaped root (F) is of this description, and many plants have it-for instance, the Carrot, Parsnip, Radish, &c. The truncated root of the Devil'sbit (G, fig. 10) is also a storehouse for the plant's nourishment; the granules of the Meadow Saxifrage (H) serve the purpose, and the Lesser Celandine stores its mucilage in bundle roots (I). Some botanists class the tubers of the Orchis (K, fig. 11) with these thickened feeding-organs, and others consider them more of the nature of underground stems.

K

Fig. 11.

But whether the granule, tuber, or spindle be present or not, the plant is supplied with fibres, simple or branched, perpendicular or horizontal. These are the mouths of the vegetable, by which it imbibes moisture and nourishment from the earth; the moisture rises through vessels and traverses the whole plant, be it herb, shrub, or tree, reaching to the leaves and the remotest bud before evincing any change; there it permeates the lungs of the plant, becomes converted into characteristic sap, and gradually descends again by a separate machinery of vessels. The structure of the woody parts of roots corresponds generally with that of the stem, only instead of pith it has in the centre a bundle of woody fibre and vascular tissue. The true root is divided from the stem by a collar, all the parts beneath the collar, whatever their form and nature, may be said to belong to the root, though they may not serve the purpose of the root. Possibly it may not have occurred to you of how great a service roots are. The utility of roots as the mouths of the plant I have already mentioned, and they are of equal importance as anchors to the plant. The roots of the Oak extend every direction as far as the branches, and this accounts for the great stability of the tree and its security amid storms and floods. The fibrous roots creep always in the direction of water; they have enormous power in penetrating the smallest crevices in rocks, encircling stones, and pushing their way through every impediment, thus making good a strong position for the plant.

in

Some roots are very aggressive in their habits. Horseradish and Mint are very difficult to restrict to the ground assigned to them; and the Couch-grass, against which the farmer preaches an everlasting crusade, finds means of overcoming every check to its progress. Dr. Murray found bulbs of the White Lily threaded by fibres of the Couch-grass like beads on a string. Yet even these obtrusive grass-weeds have their utility, binding securely the sand on the river-bank or sea-shore, and thus forming more enduring dikes than the hand of man could raise.

It sounds selfish to speak of the edible qualities of roots as their highest utility; but it is not really so, for did not God create the herb and grass of the field, and every tree, and give them to man with the clear injunction, "To you it shall be for meat?" In a spirit, therefore, of thankfulness to our beneficent Father, I would enumerate the articles of food which He has made to grow for us in the roots of plants-the Carrot, Turnip, Radish, Artichoke, Beetroot, Onion, Parsnip.

Instinct prompts the most savage nations to dig up and eat roots, and great numbers subsist upon such food, thus contenting themselves with the humblest of God's provisions. Alas! that the image of the Destroyer should so efface that of the Creator in the highest of His works, that we should hear of the fierce savage killing his own children, because the cravings of hunger prompted them to steal the roots he had dug up !

The STEM is woody or herbaceous. Herbaceous stems are soft and pulpy, composed, in a great measure, of cellular tissue. They die down in winter. Woody stems are hard and perennial, such as those of trees.

The LEAVES of plants are to them what lungs are to animals; the moisture sucked up by the root is turned into sap by the leaves, and exposed to be acted on by the air, as the blood is in the lungs; from them the sap passes into every part of the plant, causing it to grow and thrive. Each leaf has two skins, an upper and an under one, and veins variously disposed-as a network in the large class of two-lobed or Dicotyledonous

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9

plants, and in parallel lines as in the one-lobed or Monocotyledonous class.

Leaves are of various shapes. Heart-shaped leaves prevail

Heart-shaped, Kidney-shaped, Buckler-shaped, Perfoliate Sinuated or Cordate

Leaf.

or Reniform
Leaf.

or Peltate
Leaf.

Leaf.

Fig. 12.

Leaf.

in the Violet, Twayblade, and Lime; kidney-shaped in the Pilewort; buckler-shaped in the Wall Pennywort and Garden Nasturtium; arrow-shaped, as in the Arrowhead; perfoliate,

when the stem passes through it; and lanceolate when it is broad in the middle and tapering at both ends.

The edge of a leaf can be in angles, like that of the Arrowhead; plain, as in the Wintergreen; sinuated, like the Oak; toothed, like the Dandelion; serrate, as in Rose-leaves (fig. 13). Leaves are simple or compound. Of compound leaves some

are palmate-shaped, like a hand with fingers-as the Horsechestnut; some pinnate-many leaflets ranged on either side of a stalk; bi-pinnate, or tri-pinnate (fig. 14).

The grass-shaped leaf is rare, except in the second great class; but the Stitchwort affords an example among Thalamiflorals. The leaves of the Snowdrop, Crocus, Daffodil, &c., are all grass-shaped, modified in the form of their point to acute, sword-shaped, &c.; but these leaves have a different structure. We have already spoken of one broad mark of distinction between the first and second classes in the One or Two-lobed form of the seed. Another distinction equally clear and permanent exists in the venation of the leaf. In the Two-lobed class the veins of the leaf form a network, the side veins running at almost a right angle with the midrib, and the lesser veins branching off in a similar manner from them. This network venation belongs to the Two-lobed class. In the One-lobed class the veins run parallel, starting from the footstalk and continuing in a line, more or less straight, to the point. This is plainly the case in all true Grasses and in the long narrow leaves of the bulbous plants. It is no less really so in other forms of the One-lobed foliage, as, for instance, the Arrowhead, with its arrow-shaped leaves, and the Lily of the Valley (Plate XV., fig. 5), with its pointed ovate leaves. This distinctive character of the leaves is still more useful in deciding the class of a plant than the form of the seed, because the leaves are more generally present.