214 JOUENAL OF THE ROYAL HORTICULTURAL SOCIETY. 



leaf stalks and stems (fig. 81, b), perhaps more particularly at the nodes, 

 though not by any means confined to that part. Frequently the spots 

 first appear a little above the base of the stem, but they are to be found 

 in any part right up to the flower. The spots on the stem are usually 

 much paler than those on the leaves, when they first appear. 



The tissues around the spot are filled with the mycelium of a fungus 

 and the cells attacked are killed. The spots rapidly enlarge, and on the 

 leaves often run into one another. As the fungus spreads the tissues 

 right through the leaf are killed, so that the spots are evident on the 

 lower surface as well as the upper. On the stems the spots increase in 

 size lengthwise more rapidly than in diameter, so that they soon assume 

 an elongated oval form, sometimes reaching a length of two inches or 

 more. As time goes on the tissues are killed completely round the stem, 

 and subsequently the whole of the stem, above the spot attacked, wilts, 

 turns brown, and dies. The spots become darker in colour and finally 

 almost black, owing to the presence of numerous very dark brown stiff 

 bristles (fig. 81, d) standing up from the diseased spots, among which the 

 colourless spores (fig. 81, c) are produced in great numbers. 



Several correspondents have stated that the disease has spread through 

 and killed all the plants of this species in a garden, and it is certain that 

 when it once appears its progress is rapid and the havoc it causes certain ; 

 furthermore it has not proved at all easy to combat. 



The disease is caused by the fungus Golletotrichum malvarum, a 

 species which was first noticed in 1854, and described by A. Braun and 

 Caspary * under the name of Steirochaete malvarum. In 1890 South - 

 worth,t writing of a new hollyhock disease, described the same fungus 

 under the name of Golletotrichum althaeae, thus putting it in its proper 

 genus, but overlooking the fact that it had been described previously 

 under another specific name than althaeae, and under this name Massee % 

 and Cooke § refer to it. 



Until 1906 it was unknown in this country, but in that year it was 

 recorded as having been " collected by Mr. Wishart at Alyth, Perthshire, 

 on a malvaceous plant, "|| and, as we have pointed out, it has since that 

 time appeared in many parts of this country. 



Eriksson found it in a garden in Stockholm on a species of mallow 

 in 1883, and in America it has proved very destructive to hollyhocks. 

 We have not yet seen it upon hollyhocks in England, but, as it has 

 attacked them so disastrously in America, it is to be looked for upon 

 them here. The symptoms of the attack on the hollyhock are similar 

 to those described above. 



Repeated sprayings with Bordeaux mixture, while they have checked 

 the disease to some extent, yet have not sufficed to stop its progress 

 completely. This fungicide is, however, the best that is available. 

 Plants which show the symptoms of the disease should be destroyed by 

 fire as soon as possible after its appearance. Where the disease has once 

 occurred it has unfortunately reappeared in succeeding years, and it 



* XJber einige neue oder weniger bekannte Krankheiten d. Pflanzen. Berlin, 

 t Journ. of Mycol. vi. pp. 45 and 115. 

 t Textbook of Plant Diseases (1899), pp. 290, 429. 

 § Fungoid Pests of Cultivated Plants (1906), p. 39, pi. ii. fig. 43. 

 || Trans. Brit. Mycological Society, iii. p. 39. 



