Atrophy of young fruits is commonly due to the flowers not setting--_i.e._ some agent has interfered with the normal transference of the pollen to the stigma. This may be due to excessive rain washing out the pollen (_e.g._ Vine), to a lack of the necessary insects which effect pollination, often seen in greenhouse plants; to the stamens being barren--_e.g._ certain varieties of Vine--or to the premature destruction of the stigmas by frost, as in Cherries, Pears, etc., or by insects, as in Apples, or fungi, _e.g._ the infection of bilberries with _Sclerotinia_; or even by poisonous gases, as is sometimes seen in Wheat, etc., growing near alkali works. Drought is also a common cause of atrophy of young Plums. _Shanking of Grapes_ is a particular case of atrophy and drooping of the immature fruits, due to the supplies being cut off by some agency. It may arise from very various causes which bring about disease in the leaves or roots, and should always be looked upon as a sign of weakness in the Vine, the structure of which is affected, _e.g._ poor wood--or the functions interfered with, _e.g._ water supplies deficient owing to paucity of roots. Barren Apple, Pear, Plum, and other flowers are often found to have been bored through the petals while in bud, and the whole "heart" of the flower eaten out by the grubs of _Anthonomus_, leaving the unopened buds brown and dead, as if killed by frost or drought, and often erroneously supposed to be so. The wilting and shrivelling of Clover is sometimes due to _Sclerotinia_, the mycelium of which pervades the roots and stock, on which the sclerotia may be found. Lucerne is similarly killed in Europe by the barren mycelium of _Leptosphaeria_, which may be found as a purple mat on the roots. _Dwarfing_ consists in partial atrophy of all the organs, and is a common result of starvation in poor, dry, shallow soils, as may often be seen in the case of weeds on walls or in stony places. Dwarfs which are thus developed in consequence of perennial drought are not, however, necessarily diseased, in the more specific sense of the word; their organs are reduced in size proportionally throughout in adaptation to the conditions, and simply carry out their functions on a smaller scale. Dwarfing is frequently a consequence of the lack of food materials, or of some particular ingredient in the soil, and in such cases is a diseased condition of some danger; similar results may ensue in soils containing the necessary chemical elements, but in unavailable forms.