IN the First Series the common wallflower is described under its generally accepted name of Cheiranthus cheiri. The plant before us bears a name which indicates its close relationship to the wallflower proper, and it is also known as Erysimum ochroleucum, which connects it with the common treacle mustard and other four-parted yellow flowering plants of like character. The true wallflower is of universal use in gardens, its sturdy growth, brilliant colours, and fresh spicy fragrance insuring for it general acceptance as one of the most delightful products of spring. The so-called Alpine wallflowers are not of universal use; but, on the other hand, they have some special claims on our regard as valuable adornments of the rockery and the choice border.

The Alpine wallflower (E. ochroleucum) forms a neat leafy bush, nine to twelve inches high, adorned in spring with a fine head of sulphur or pale lemon-coloured flowers. Like the garden wallflower, it is well adapted for planting on walls and ruins, but unlike the more fragrant plant, it is not adapted for the common border, by reason of its susceptibility to winter damp. It is as hardy as any plant of its class, and therefore frost will but rarely harm it, provided it is on a dry soil, and has not become over-luxuriant through good living. It is a point of great importance for the amateur grower of Alpines to bear in mind that the promotion of a free succulent growth is altogether undersirable in the case of all such plants; many of them require an abundance of moisture in their growing season, but a rich soil and a position removed from the free atmosphere and the full play of the daylight are, generally speaking, directly injurious, both as rendering the plants less hardy than is their nature, and also less disposed to flower freely. We often have to recommend a deep nourishing loam or peat for Alpine plants, but it may be observed that we never recommend the use of stimulating manures or soils that are naturally damp and heavy. The mountain flora comprises plants that vary immensely in affinities and requirements; some are at home on the dry, starving rocky bluff, where there is scarcely a particle of such stuff as we call "mould;" others haunt the crowded bog, where the plants form a dense wet mat, and subsist on the black earth that results from the ever-accumulating decay of those that have lived their season or have been stifled by the strong usurpers. But a large proportion of the most beautiful Alpine plants have their roots in deep beds of decayed stone, containing always some amount of moisture, but often in the summer being saturated with water, owing to the melting of ice and snow on the peaks above them. Those beauties that are so much prized in our gardens will generally thrive on the rockery where the soil consists of sandy loam, with some proportion of calcareous matter, and the drainage is sufficiently perfect to insure that there shall be no lodgment of water in the winter season. As for the Erysimums, a poor soil and full exposure are the chief requisites.

The Lilliputian wallflower (E. pumilum) is a pretty little Alpine with greyish leaves, the whole plant rarely exceeding one inch in height, but bearing yellow flowers of the same general character as the plant before us. This requires the best of care in its cultivation, and should be seated amidst stones, both to insure continuous moisture for its roots and to protect it from harm.

The Rhoetian wallflower (E. rhoeticum) is a beautiful little thing, worth a place on the choicest rockery. The rock wallflower (E. rupestre) and the fine-leaved wall-flower (Cheiranthus tenuifolius) may be added to the budget as a couple of very choice subjects. The last named has long narrow leaves and a short flower-stem, bearing rather large pale yellow flowers.

The lance-leaved treacle mustard (E. lanceolatum) claims notice as a somewhat important plant, the names it bears in the books being at least twelve in number. It comes near to our Alpine wallflower, but differs in growth and leafage. Whatever its exact place, it may be made note of as a good rockery plant; it has two forms, the major and the minor, the last named being the best. The flowers are of a lemon-yellow colour, very agreeably scented.

Returning to the garden border, where the more robust and fragrant wallflowers show their cheerful green all the winter, and their golden, fiery, and sanguinary flowers in spring, mention should be made of two species of Erysimum that are renowned for the splendour of their flowers.

One of these is the Persian treacle mustard (E. Perofskianum), a splendid annual, received at the Edinburgh Botanic Garden in 1838 from Dr. Fisher as a native of Cabul, but in B. M., 3,757, it is described, on the authority of Lady Mary Cathcart, as a native of Persia, where it is as great a favourite as the wallflower is with us. This beauty is usually grown from seeds sown in autumn, but the seeds may be sown in March and April.

The other plant is Marshall's wallflower (Erysimum Marshallianum), also known as Cheiranthus Marshalli. This is always grown from cuttings, as it never or but rarely produces seed. It forms a neat little bush, which in early summer produces a profusion of showy flowers of a buff-tinted apricot. In the early days of the bedding system it was much employed in geometrical colouring.