6l6 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



neighbouring parts of Brazil. The gardens have apparently suffered 

 considerably from past neglect, but during the short time that Dr. 

 Willis has been in office as Director great improvements have been 

 effected. Adjoining the gardens there is a forested slope which has 

 been taken over by the Brazilian Government for the cultivation of 

 useful trees, but the work of clearing parts of the area for this purpose 

 is evidently a difficult one, for wherever the trees are felled the lianas 

 and climbing bamboos multiply and make an almost impenetrable 

 jungle, so that in many respects the gardens and their vicinity are still 

 of perhaps greater interest to the ecologist than to the economic 

 botanist. The extraordinary richness of the flora in and around Rio 

 is shown by the fact that no fewer than ii,ooo species are knov/n from 

 the Federal Area in which the city is situated, an area of about the 

 same extent as the County of London and largely covered by buildings. 

 Though forest trees predominate in the gardens themselves, there are 

 open spaces where European and tropical flowers flourish bedded side 

 by side as in an English park, but the great features are the palm 

 avenues, the bamboo plantations, fine groups of the huge Musaceous 

 Ravenala madagascariensis , very fine collections of Cycads and Conifers, 

 sections devoted^to families like Aroideae and Marantaceae, and a 

 large pond of Pontederiaceae and other tropical aquatics. — F. C. 



Brown-rot Fungus, A Study of the. By J. L. Conel {Phyto- 

 pathology, iv. p. 93 ; April 1914). — The brown-rot dealt with is said 

 to be Sclerotinia cinerea, not 5. fructigena, producing the rot mainly 

 on stone fruits, but occurring also on pome fruits. The conidia found 

 on the mummy fruits survive the winter in many cases. Infection 

 experiments were carried out, and while plums were very readily 

 infected, apples were also attacked, but less vigorously. — F. J. C. 



Carbon Supply to Garden Plants. By H. Fischer [Gartenflora, 

 vol. Ixiii. pp. 125-132). — A new series of experiments shows that 

 the addition of carbonic acid to the atmosphere not only assists the 

 growth of plants, but also induces them to flower earlier and more 

 freely. This confirms the author's previous results. Increased crops 

 were also obtained in the open, when carbonic acid gas was supplied 

 to the roots, through a system of perforated pipes, laid at a depth of 

 4 inches in the seed-bed. The gas was supplied to the bed every 

 bright morning, a fortnight after the seed was sown. — 5. E. W. 



Catasetum. By H. Memmler {Orchis, vol. viii. pp. 19-23). — The 

 varieties of Catasetum may be divided into four sections. 



I. Eucatasetum. The plants are dioecious, and the labellum is 

 inserted above the flower. The rostellum is prolonged into two 

 antennae. C. atratum, C. Gnomus, C. macrocarpum, C. purum, C. 

 macroglossum, C. Naso, C. viridiflorum, C. maculatum, and C. Wailesii 

 belong to this section. 



II. Myanthus. Dioecious plants. The labellum in the male is 

 below, and in the female above the flower. This group embraces 



