784 



JOURNAL OF THE KOVAL IIOKTICL'LTLKAL SOCIETY. 



venes it means the destruction of all the chestnuts in the Atlantic States. 

 No efficacious treatment for the prevention of the trouble has yet been 

 found. 



(b) Investigations with artificial cultures of Phytophthora were 

 carried out with two points chiefly in view : — • 



1. To obtain a perfectly satisfactory medium; Lima bean juice 



agar proved to be the best. 



2. To determine if Phijtophthora possesses mycelia of distuict 



sexual strains. 



The writer inoculated Lima bean juice agar with mildews from 

 different sources. Although the cultures were not extended enough to 

 speak positively, no unusual mycelial development or formation of 

 oospores was observed. Attempts at crossing Phyiophthoro. infestans 

 and P. phaseoli (the latter only is capable of producing oospores) gave 

 rise to certain immature oogonia which were larger, somewhat thicker- 

 walled, and of a darker colour than the ordinary oogonia of P. phaseoli. 

 the oogonia were found at the junction of the two colonies, and within 

 the area occupied by P. infestans. The author takes these results to 

 mean that P. phaseoli grows more aggressively than P. irijestans, and 

 where it comes in contact with the latter has to form its oospores under 

 unfavourable conditions, due to toxins in the media produced by 

 P. infestans. 



Plates showing the different stages of development of oospores in 

 Phytophthora phaseoli are given. — D. M. G. 



Diseases (Parasitic) of the Cinnamon Tree in Ceylon. 



By D. Bois and 0. Gerber {Ann. Jard. Bat. Buit. 3rd supp. 1st part, 

 1910, pp. 109-116; with 8 figs.). — Two types of gall occurring upon ! 

 the leaves of Cinnamomum zeylanicum are described in this paper. 

 In the one type the gall usually forms conical projections upon the 

 upper surface of the leaf and possesses a minute aperture on the lower 

 side of the leaf. No deformation of the leaf is caused by this form of 

 the gall. 



The other type of this gall usually occurs upon the lower leaf- 

 surface, and its apex is perforated by a small aperture. Considerable 

 distortion of the leaf is caused by this form of the gall. 



The interior of the gall is chambered and furnished with hairs. 

 The. gall is caused by a mite, Eriophyes Boisii Gerb., which is figured 

 and described in this paper. — R. B. 



Doubleness in Flowers : Petunia. By E. E. Saunders {Jour. 

 Gen. i. pt. i. p. 57). — The double flowers of Petunia are described. 

 In the breeding experiments wliich are detailed single Petunias belong- 

 ing to the forms wliich were experimented with (viz. Petunia violacea, 

 P. nyctaginiflora, P. hyhrida grandiflora, and P. ' Countess of EUes- 

 niere '), whether self-fertilized or crossed with each other, yielded only 

 singles. Cross-bred singles derived from one single and one double 

 parent produced singles only, whether self -fertilized or fertihzed inter 

 sc. Singles crossed with pollen from a double yield doubles in the first 



