JULY 28, 1S97.] 



Garden and Forest. 



293 



excurrent growth with small horizontal branches and most of 

 the wind-exposed surface toward the base. The latter tree has 

 rather brittle wood, which breaks under comparatively little 

 transverse strain. Gleditschia triacanthos, with its wide- 

 spreading top and slender branches, we should expect to find 

 much injured, but even isolated trees have stood well. The 

 wood is strong, tough and elastic, and the finelydivided leaves 

 are not sufficiently abundant to offer much resistance to winds. 

 Among those trees thatescaped almost uninjured is Taxodium 

 distichum, the Bald Cypress. The tall pyramidal shape which 

 this tree takes in cultivation in our parks, so different from the 

 wide-spreading tree of the southern swamps, offers very little 

 resistance to the wind. The strong, elastic, almost whip-like 

 trunks simply swayed back and forth in the gale without 

 breaking or uprooting. Other conifers like the heavier Pines 

 were uprooled. 



A Chrysanthemum Disease. 



LAST season the attention of this Department was called 

 _j to a peculiar disease of Chrysanthemums in this sec- 

 tion, which was confined wholly to the variety Philadelphia. 

 Mr. Robert Miller, of Messrs. Strauss & Co., first noticed 

 the trouble which had appeared on his plants while he was 

 absent for a week. Although other varieties were in the 

 same house with the Philadelphia and on the same bench, 

 they showed no evidence whatever of the disease. The 

 affected plants had numerous yellow spots or blotches on 

 the leaves. The spots were irregular in size and shape 



Fig. 37 — Sun-print of a diseased leaf of Chrysanthemum Philadelphia. 



and stood out in striking contrast to the green portions of 

 the leaf, especially if the latter was held between the eye 

 and the light. In the case of Mr. Miller's plants, the leaves 

 formed during his absence were most seriously affected, 

 while those which had developed after he had taken per- 

 sonal charge were in most cases free from the trouble. In 

 many instances a minute puncture was found near the 

 centre of the spots. From this and other facts it seems 

 probable that the disease is due to some inherent charac-' 

 teristic of the variety, by virtue of which it reacts quickly 



to any injury either in the shape of insect bites or punc- 

 tures, improper watering or feeding, etc. The variety, in 

 other words, is constitutionally weak and needs only a very 

 slight disturbance to cause a local breaking down of the 

 cell contents, followed by the effects already noted. Sev- 

 eral insects were present on the plants, notably leaf-hop- 

 pers, aphides (green and black), and a species of thrips. 

 These insects were present, however, to a limited extent 

 everywhere in the houses, and the marks of their bites and 

 punctures were seen, unaccompanied by any further inju- 

 ries except in the case of the variety named. Figure 37 is 

 an illustration from a sun-print of a diseased leaf. The 

 dark spots in the picture show the position of the yellow 

 discolorations. It would be interesting to know if this 

 disease attacks the same variety elsewhere. 



It may be well to call attention here to the fact that there 

 are many cases of yellow spotting of the leaves of green- 

 house plants which can in most cases be traced to an 

 improper use of water in its application to the soil and to 

 a neglect of the right conditions of temperature, humidity, 

 etc. , in the houses. It is unnecessary to go into all the 

 details of the changes in the vital functions of the plant 

 which may take place under such conditions. Suffice it to 

 say that as the tissues become waterlogged, groups of cells 

 being thus disabled from manufacturing food, use up what 

 they already contain, and when this trouble reaches a cer- 

 tain point yellowing and other changes follow. When a 

 plant gets into this abnormal condition the bite or puncture 

 of an insect will often hasten the changes, which eventually 

 result in the formation of yellow, brown and various 

 colored spots. Certain fungi, too, find these more or less 

 disorganized areas excellent feeding ground, so that they 

 come in and complete the work. Too often only the 

 insect or fungus is seen and considered, the fact being 

 overlooked that they are only links in a chain, as it were, 

 and oftentimes not very important ones at that. All this 

 means that to be successful with plants under glass or 

 anywhere else we must first learn to know them, feel their 

 needs, and thus be able to keep them healthy, vigorous 

 and productive. In many cases the presence of insect 

 pests and fungous diseases is only evidence that the grower 

 is not in close touch with his plants ; that he is neglecting 

 some of the fundamental principles underlying their growth, 

 and that until these principles are recognized he cannot 

 hope to attain the highest success in his art. 



Dept. of Agriculture, Washington, D. C. B- T. Galloway. 



Foreign Correspondence. 

 London Letter. 



Kalanchoe flammea. — This is a new introduction from 

 Somaliland which is now flowering for the first time at 

 Kew. It possesses all the characters of a distinct and beau- 

 tiful greenhouse plant, so that it is certain to become pop- 

 ular. The stems are erect, about a foot high, clothed with 

 opposite spathulate fleshy leaves from two to three inches 

 long, and an erect, long-stalked sub-paniculate cyme of many 

 bright scarlet flowers, brilliant as a soldier's coat. Each 

 flower is three-quarters of an inch wide, or about the same 

 size as the flowers of Crassula coccinea, and as they are 

 sub-umbellate they present heads five inches across. The 

 plant has been in flower a month or more and will last for 

 some weeks longer. It produces basal growths freely and 

 promises to ripen seeds. The genus Kalanchoe consists 

 of about thirty species, chiefly native of tropical Africa. It 

 is related to Crassula. 



Vitis Voinieriana. — This is a suggested new species in 

 the way of Voinieriana antarctica, but of much larger pro- 

 portions. It is being distributed by Monsieur Sallier, 

 nurseryman, Neuilly, France, who recommends it for out- 

 side cultivation in the west and south of France and for 

 winter gardens in England. It has been received by- 

 Monsieur Charles Baltet from Monsieur Voinier, of Tonkin, 

 who found it on the Nin-Binh mountains in Laos, where it 

 clambers over rocks, etc., like Ivy, but so vigorously that, 



