228 THE FLORAL WORLD AND GARDEN GUIDE. 



exceedingly useful. P. Gordoniamis ia later than the others, and 

 has the showiest flowers, but they are quite scentless. Prunus tri- 

 loba is one of the prettiest of spring-flowering shrubs ; the flowers 

 are in the form of neat rosettes, and of a delicate pink colour. 



Sijringa vulgaris Charles X., S. vulgaris Dr. Lindley, and 8. vul- 

 garis alba, are, perhaps, the roost -valuable of the lilacs. The two 

 first mentioned are grand varieties of the common lilac, and should 

 be planted in preference to all others. 



The Guelder Eose, Viburnum opulus, and the more recently 

 introduced F.jjZ<(?ato??i, are two strong-growing shrubs, useful for 

 grouping with others in large masses. The last-mentioned has the 

 largest flowers, which also are the purest in colour. 



The Weigelas are very beautiful in kind climates, where they 

 have a chance of growing to a considerable size, but they are tender 

 in the neighbourhood of London, and further north. They suffer 

 so much from spring frosts when on cold, damp soils, that, in the 

 course of a few years, they perish outright. JV. amabilis, and its 

 beautiful variety rosea, are both well known. W. Middendorffiana 

 purfurata is a variety at present but little known in this country, 

 and well deserving of the attention of cultivators resident in shel- 

 tered situations, where Weigelas, and other plants of a similar 

 character, thrive. The flowers are rich in colour, and well estab- 

 lished plants have a most beautiful appearance vrhen in full bloom. 



THE ENEMIES OF THE ELM. 



BY A PKACTICAL FORESTER. 



[HE elm, one of the most noble of our park and forest 

 trees, is subject to the attacks of several insect enemies, 

 which, whether they are the cause or the result of a bad 

 state of health, are capable of doing a considerable 

 amount of mischief, and also of hastening the death of 

 the trees that they attack. The enemies with which the elm has to 

 contend in the battle of life, are the larva of Bostrichus chalco- 

 r/rapJius, B. topograplius, Cossns liffniperda,hetter]s.no\^n as the goat 

 moth, Hijlisimus fraxini, Scolytus destructor, and Cossonns linearis. 

 The Scolytus and the Cossonus are the two foes most to be feared, for 

 they are multiplied at a very rapid rate when they once attack a tree, 

 and the larvoc of the first- mentioned of the two have the power of 

 penetrating the sound hard wood, as well as of feeding on the liber 

 or inner bark, and on the alburuum. The larvae of the Scolytus 

 feed entirely upon the alburnum, and they are perhaps more fatal in 

 their eff"ects, for by eating this asvay the flow of sap is more or less 

 checked, and in the end the tree, if badly infested, perishes. The 

 Cossonus is very small, and as Mr. Humphreys, in an interesting 

 article on the " Insect Enemies of the Elm," in vol. ii. of the Intel- 

 lirctual Observer, remarks, " The larva is, as may be conceived from the 



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