Smoke and dust are bad enough, but when in addition, we have to contend with the London fogs, it is then that Alpine and rock plants fare worst. The chemical impurities of a foggy town atmosphere, which often are positively hurtful to the eyes, are deadly to plant life generally, and, after a continuation of two days, the leaves of many plants, not only out of doors, but in our plant houses as well, fall off prematurely as if seared by frost or fire. So bad are these fogs, the dense yellow in particular, that after a continuance of two or three days the accumulation of greasy, sooty deposit on the glass renders the plant houses quite dark within and resort to washing is imperative. The following observations on such rock and Alpine plants as have been found most suitable for planting in a town garden are the result of many years of study and experiment, and have, in the main, been collected from several of the most smoke-infested parts of London and other large cities.

Probably the best all-round plants for the rock garden are the various species of dwarf Iris, many of which will not only succeed but absolutely flourish, where soot and smoke are the order of the day. In corroboration of this we have only to visit some of the gardens in the East End of London, or at Lambeth and Bermondsey, and see how well these plants are suited for doing battle with the impurities of a town atmosphere. In the grounds of the Royal Mint or in the gardens attached to the Tower of London, where the atmospheric conditions are too well known to require comment, the various kinds of Iris flourish amazingly. Even in dry, poor soil, the appearance of which strikes one as sooty in the extreme, the commonly cultivated species thrives in a commendable way and goes on steadily increasing from year to year.

Some of the best varieties of the Iris for rockwork are I. ochroleuca, I. sibirica, I. germanica, I. gigantea and I. Pamila in variety. Of that most useful of rock plants the Saxifrage, few are really suited for growing in London, by far the best being the well-known London Pride (Saxifraga umbrosa), which, as an all-round showy evergreen for smoky localities, has few equals. 5. ccespitosa is another excellent species and thrives well in the very heart of the great metropolis. 5. Andrewsii and 5. dentata have also done well for seven years in a town garden. Curious as it may appear the choice little Azalea procumbens, from the highest granite mountains of Scotland, has become quite established in a London garden, where the air must be vastly different from that at the high altitude at which it is found growing naturally. The nearly allied Arctostaphylos Uva-ursi (the Bearberry) has also done well, and in one instance increased from a small plant till it now covers quite a square yard of ground surface. An excellent shrub for town planting is Genista sagittalis, which to my knowledge has grown and flowered freely on a rockwork in the centre of London for the past ten years. Another excellent Alpine is the Prophet Flower (Arnebia echioides), which for many years has charmed us with its curious yellow flowers, the black marking of which gradually gives way with age and from which the popular name of the plant was given. Several species of Campanula actually revel in the town atmosphere, notably our native C. Trachelium and C. rapunculus, both of which may be seen in various parts of London running about rampant and flowering profusely. Of the more showy flowered kinds, the most notable for surviving where the air is chemically impure are C. carpatica, in variety, C. persicifolia (various varieties), C. turbin-ata, C. lactiflora, C. punctata, and C. rotundi-folia, a patch of the latter having flowered annually in a town garden for the past eight years. Two other desirable kinds are G. F.

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Wilson and Van Houttei. Auriculas are well adapted for and most useful on the town rockery, where they flower with the utmost freedom; which also may be said of that useful wall plant the Toadflax (Linaria cym-balaria). The free growing and remarkably handsome L. pallida also does well and produces its flowers in profusion, while L. hepaticifolia and L. hederacea are also desirable. Few species of Primula are adapted for smoky localities, though the too little known P. Sieboldii has been found peculiarly suited for the London garden, where it flowers and increases freely. Amongst Orchids that I have found amenable to cultivation in the town garden, particular mention may be made of the Mocassin Flower (Cypripedium spectabile) and the English Lady's Slipper (C. Calceolus), the former having become established in a shady, dampish corner of my garden, where it annually produces from six to fifteen flowers. Growing in the company of Empetrum and Vaccinium the Madeira Orchid (O. foliosa) seems to grow and flower by the pond side in Regent's Park.

Aster alpinus has also survived and flowered freely for a number of years where constantly subjected to smoke, dust, and other impurities which are connected with a town atmosphere. Calceolaria Polyrhiza has become quite established and increases rapidly in the town garden, the single deep yellow flowers being freely produced. Two species of Willow also thrive, these including the choice little Salix reticulata, with its beautifully reticulated leaves and neat procumbent habit of growth, and the equally choice and dwarf S. herbacea. Neither has received any particular care as to choice of soil or site. Arabis albida and its double flowering variety are both useful plants for the rock garden, where they increase and flower freely. Statice Spathulata and the neat dwarf S. speciosa have both thriven well in a town garden for the past ten years. They are interesting evergreens, with pretty lilac, almost everlasting flowers, and seem to succeed best when planted in gritty loam and in full sunshine. Several of the Rock Roses (Helianthemum) have become quite established in a London garden, where they have received little attention either in the matter of soil or site. They certainly like sunshine and not too heavy soil. There are many worthy varieties. The conspicuous Me-gasea cordifolia must not be omitted from a list of town plants, as in many places it not only flowers freely but goes on increasing in size and strength from year to year.