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PLOUGHMANS SPIKENARD (Inula Conyza)

Two kinds of Plume Poppies are commonly grown as hardy herbaceous perennials. These, B. cordata (Syn. B. japonica) and B. microcarpa, bear cream and bronzy flowers respectively from June onwards, and both have attractive foliage. The former averages 4-7 ft. in height, while the latter may reach a height of 9 ft. Light rich soil suits them, and propagation by root division in the early spring is not a matter of any difficulty. Their height and general character makes them suitable for shrub borders or for the back rows of hardy perennial parterres.

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POPPY MALLOW (Callirhoe Nat Ord Malvacese)

This, the most destructive of all potato diseases, is caused by the microscopic fungus named Phytophthora infestans, which not only attacks and blackens the haulm but also destroys the tubers. In 1845 it devastated the potato crop in Ireland, causing widespread suffering, and ever since that date has been recognised as a serious menace to potato growing. The disease starts as a rule in June or July, when the well-known black patches appear on the leaves accompanied by the delicate white mould on the under surface. It is the presence of this white or grey mould around the affected areas which distinguishes Blight from black spots on the leaves caused by aphides and other agencies. If the weather be damp and warm the disease spreads rapidly, plant after plant becoming affected and the haulm blackened and destroyed. If, on the otherhand, the weather turns dry the disease is checked, in fact the intensity of attacks of Blight in this country are almost entirely dependent on the nature of the season. It is, of course, by means of spores that the disease is distributed. These are produced on the white mould seen on the affected leaves ; they are readily carried by rain, wind, insects, etc., from plant to plant, and if the climatic conditions are favourable they germinate and cause new patches of disease from which innumerable fresh spores are liberated within the course of a few days. The disease in the tubers is the result of the presence of the fungus in the leaves. Spores fall in profusion from affected leaves, and finding their way to the tubers present in the soil, readily infect them. Those tubers nearest the surface are naturally most seriously affected. A large amount of infection also takes place whilst the potatoes are being lifted, spores being blown from diseased haulms on to the tubers. The tubers at the time appear to be and are healthy, but the spores germinate and infect them, and later on the effect is seen by decay in storage. The infection of tubers can be easily detected by the presence of dark, depressed areas which it will be noted are usually on the upper surface. Inside the tubers the result of the fungus invasion is seen in the formation of the well-known brownish-red patches. Spore infection so far as is known is the only way by which tubers become affected. No scientific support has been found for the theory formerly held that the mycelium of the fungus passes down inside the haulm and along the rhizomes into the tubers. The rapidity with which decay takes place varies with the time of year and differs also in different varieties. In some varieties decay is slow, in others, such as British Queen, very rapid rotting may suddenly occur during autumn when tubers have been clamped. During the winter and spring, however, a large amount o

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PRUNELLA (Self-heal Nat Ord Labiatae)

A popular name of Hydrocyanic Acid, which see in A ciDS : Their Uses in Horticulture.

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