306 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY, 



When the cultures were dried, and then again wetted, a greater number 

 of seeds germinated. — G. F. S.-E. 



Germination of Orobanehaceae. By S. Kusano (Beih. Bot. 

 Centralbl. vol. xxiv. Abth. 1, Heft 3, pp. 286-300 ; April 1909 ; 2 plates).— 

 Professor S. Kusano describes (in English) the seedling of Aeginetia indica 

 and its method of attacking the host plant. The minute few-celled 

 embryo has at the radicular end about 15 globular epidermal cells. 

 Oce or more of these cells grow out into hairs which search for the 

 root of a host plant. Many such hairs develop if no contact is at first 

 effected. But on touching such a root, the hairs appear to grow in 

 between its cells ; they then contract, curving in like a tendril, and so 

 bring the little embryo into contact with the root. The embryo then 

 grows rapidly, becoming visible to the eye, and forms a primary absorbing 

 tissue or haustorium which penetrates the host plants and develops 

 tracheids in connection with the conducting system of the latter. 



The roots of many plants appear to excrete some kind of stimulating 

 substance which is necessary for the germination of the Aeginetia seeds, 

 but further development only occurs near the roots of its regular host 

 plants. 



Seeds wrapped in filter paper and placed near such roots germinated, 

 but if covered by several layers of paper fewer were able to do so. So it 

 seems probable that a definite stimulating substance is excreted by the 

 roots. The host plants were grown in pots and the seeds placed on the 

 inside of the pots in the meshwork formed by the roots. — G. F. S.-E, 



Gooseberry Mildew, American, in Germany. By R. Schander 

 (Intemat. phytopath. Dienst. vol. i. No 4, 1908, p. 97 ; 3 maps in text). — 

 Deals with the distribution of this pest in Germany up to the year 1907. 

 Spraying with a 1 per cent, solution of potassium sulphide retards the 

 development of the fungus, but it cannot be regarded as a satisfactory 

 method of control. Cutting off the twigs on which the perithecia are 

 found in winter and those affected with mildew in summer is stated 

 to be the best means of prevention. In one or two cases sickness is 

 said to have been caused by the eating of affected berries, both by adults 

 and by children (in one case a child aged If year died), but in a number 

 of other cases no ill effects followed after eating affected berries. About 

 forty cases were noticed in which the red currant was affected by the 

 same fungus, and it also occurred on Bibes alpinum and B. aureum and 

 was artificially inoculated on B. atropurpureum. The author considers 

 it advisable in districts where the disease makes its appearance for the 

 first time and to a slight extent to completely destroy the affected 

 bushes, but in districts where the disease has already got a firm footing 

 this is not to be recommended ; here the above-mentioned methods of 

 cutting off and thoroughly destroying the affected twigs should be 

 resorted to. The American Mountain Gooseberry, a derivative of B. 

 Cynosbati, appears to be immune, but unfortunately it bears only small 

 fruit. It is suggested that attempts should be made to produce a disease- 

 resistant variety. [Eriksson has found (1909) that in Sweden, at any 

 rate, the American Mountain Gooseberry is not actually immune but only 

 less susceptible to the disease]. —G. H. P. 



