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FLORA AND SYLVA, 



THE DISEASE OF CLEMATIS. 



Though the gardening press maintains a dis- 

 creet silence upon this mysterious disease, it 

 must not be supposed that its ravages have 

 ceased. Let us hope, however, that this silence 

 is neither that of resignation or despair, for, 

 however difficult the plague may be to com- 

 bat, these fine plants are worth fighting for. 

 Many suggestions, mostly guesses, have been 

 set forward as to the causes at work, one of the 

 commonest, and, to my mind least grounded, 

 being the attempt totrace connection between 

 the presence of tiny worms upon the roots 

 with the sudden destruction of the whole or 

 part of the branches. It is well, before hazard- 

 ing such theories, to try to locate the disease 

 and fix its nature and effects. In my opinion 

 it will prove to be of germ origin, for all the 

 symptoms point to this. It is probably by slight 

 wounds in the tender growths that the enemy 

 makes its attack. After violent rains, during 

 the damp heat of summer, and in low places 

 where moist air remains stagnant, its ravages 

 are most seen; on the other hand, few traces 

 are found during dry weather, resulting either 

 from heat or northerly winds, and it works 

 little harm on breezy uplands, particularly if 

 the soil is light and porous. Frequently, too, 

 the disease comes as a sequel to the work of 

 training and tying, especially when neglected 

 plants have been disentangled and wounded. 

 So much is this the case that many growers 

 either leave the plants entirely alone, or follow 

 their advance so closely as to allow of no such 

 injury, and by these means escape loss. I have 

 seen the phrase " Black Death," often applied 

 to this disease, explained as due to the blacken- 

 ing of affected plants, but its author was 

 plainly unaware that Clematis always blacken 

 after death from whatever cause. This ex- 

 pression applies rather to the point first at- 

 tacked,which is usually a narrowband, varying 

 from a fraction to more than an inch wide, and 

 generally just at the surface of the ground, 

 though it may come a trifle higher or lower 

 as the case may be. This diseased tissue is full 

 of a black dust, but whether the cause or the 

 result of decay is not clear, while of the stem 

 little remains save the main fibres, which break 

 at a touch, while the entire growth dries sud- 

 denly from this point upwards. A fact, how- 



ever, of importance is that, not only are the 

 tissues below the point of attack perfectly 

 sound, but any stems not themselves attacked 

 are equally healthy, and that, as frequently 

 happens, new growth starting from below, 

 providing it escapes contagion, is as sound and 

 vigorous as that of any healthy subject. Under 

 these circumstances one cannot well attribute 

 to the roots a disease showing only on the 

 branches, and which, when the roots are good, 

 is repaired so naturally by sound tissue. Any- 

 one may test the matter by an examination of 

 the roots, when it will be found that if a cer- 

 tain number of plants show worms, a good 

 proportion, particularly of the younger plants, 

 are quite free from them, and yet the results 

 are the same in both cases, the only thing 

 proved being that, as might well be expected, 

 the plants whose roots are most beset with 

 worms recover but slowly. There are other 

 interesting observations to be made upon this 

 subject, such as the indemnity of the types, 

 and of certain races, but for the moment my 

 aim is rather to correct a mistaken theory, 

 which by confusing issues might hinder the 

 effective study and cure of the disease. — 

 Francisque Morel, in The Revue Horticole. 



GUAVAS AND THEIR SUC- 

 CESSFUL CULTURE. 



Though closer relations with the West Indies 

 tend to the increased use of tropical fruits, 

 Guavas are as yet rarely seen in this country, 

 and the trees themselves, though easier to grow 

 than many fruits under glass, are only to be 

 found here and there. A number of species 

 exist scattered over the tropics of America and 

 the West Indies, but of these only three or four 

 I have any great value, these being the Straw- 

 berry Guava {Psidium Catt/eyanum) ; the Apple 

 Guava (P. Guava) ; its commoner form known 

 as the Pear-shaped Guava (P '. pyriferum) ; and 

 the Gooseberry Guava (P. pygmeum), with a 

 small but finely flavoured fruit. The two kinds 

 most grown are the Strawberry and Pear-shaped 

 Guavas, both of which are fruited in the open 

 air upon sheltered walls on the Mediterranean 

 coast between Hyeres and San Remo, while 

 quantities have of late years been planted in 

 Algeria. With a little care heavy crops of fruit 

 are secured each autumn, fruits equally good 



