l6o JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



The loUowing is the author's view regarding hybrids : 



M. villosa Huds. = rotundijolia X [longijolia X viridis). 



M. Maximilianea F. Sch. = aquatica x rotundifoUa. 



M. dumetorum Schult. = aquatica X longijolia. 



M. piperita Huds. = viridis X aquatica. 



M. verticillata L. = arvensis X aquatica. 



M. gentilis L. = arvensis X viridis. 



M. rubra Smith = verticillata X viridis. 



M. dalmatica Tausch. = arvensis X longi flora. 



M. carinthiaca Host. = arvensis X rotundifoUa. 



The descriptions of forms and varieties are arranged in a key, 

 and may be clear enough if the reader can manage to remember the 

 abbreviations used by the author. — G. F. S. E. 



Michaelmas Daisies. By S. T. Grignan, Rev. Hort., p. io8, 

 March i, 1914 ; coloured plate). — The plate represents a group of 

 pretty varieties, of which ' Lutetia Rose ' is by far the best, having very 

 large rose-lilac flowers, which it bears abundantly on plants scarcely 

 2 feet high and compact. It is a cross between Aster microcephalus 

 and A . novi-belgii, and clearly a worthy acquisition as regards both 

 habit and floriferousness. — C. T. D. 



Millipedes and Centipedes {Joiir. Bd. Agr., vol. xxi.. No. i, 

 pp. 46-49 ; fig.). — ^The article deals mainly with the life-history 

 and habits of millipedes and discusses the various methods of com- 

 bating the pests. — A. S. 



Mutation, A Purple-leaved, in Hemp, By L. H. Dewey {U.S.A. 

 Dep. Agr., Bur. PI. Ind., Circ. 113 ; Feb. 1913 ; pp. 23 and 24). — A 

 singular mutation, showing strongly-marked colour variation in foliage 

 and seed, arising from a closely-inbred strain of a uniform group 

 of plants.—^. P. 



Narcissus Bulbs, A Disease of. By G. Massee {Jour. Bd. Agr. 

 vol. XX. No. 12, pp. 1091-1093 ; plate). — During 1913 the disease of 

 Narcissus bulbs caused by the parasitic fungus Fusarium bulbigenum, 

 Cooke and Mass., increased to such a serious extent that in some cases 

 entire plots of bulbs were completely destroyed. As a rule the presence 

 of the parasite is first indicated by the appearance of small yellowish 

 spots on the leaves. These gradually increase in size, becoming brown 

 and dry, and the trouble spreads to the bulb by the extension of the 

 mycelium, and probably also by a series of independent infections 

 from spores washed down from diseased patches higher up the leaves. 

 At first the tips of the scales only are injured, as indicated by a brown 

 colour ; but the injury gradually extends to the base, and soon the 

 entire bulb is of a uniform brown colour. At this stage numerous 

 chlamydospores or resting-spores are produced on the mycelium 

 present in the substance of the scales, and these, being liberated into 

 the soil when the bulb decays, serve to infect future crops. Moreover, 



