336 JOURNAL OF THE EOYAL HORTICULTURAL SOCIETY. 



trees in the oats plot was due rather to the length of the drought pro- 

 duced than to the degree of dryness reached. 



The Indian corn plot did not become dry till the middle of July, by 

 which time the trees had made their growth and could more safely bear 

 the lack of moisture. 



In the matter of winter-killing, however, the results were quite the 

 other way. Of three plantations of trees, eight in each, one was sown 

 with millet, one with oats, and one was kept cleanly cultivated till 

 October, and in this last plot three trees died during the winter and the 

 rest were badly injured. In the plot sown with oats none died and five 

 were injured. In that sown with millet none died and only three were 

 injured. This difference was to be accounted for by the fact that the 

 presence of a cover-crop stopped the growth of the trees much earlier in 

 the season, and gave them more time to mature their wood thoroughly 

 before winter. 



Plates are given showing the great difference in maturity between 

 twigs cut in the middle of September from trees on the late- cultivated 

 plot and from those under a cover-crop. — M. L. H. 



Orchid Disease, New. By G. Massee (Gard. Chron. No. 93, p. 153, 

 fig. 53 ; Aug. 19, 1905). — The fungus causing this disease is Hemelcia 

 americana, which has recently been found in two different places on the 

 leaves of Oncidiums. It belongs to the same genus as the well-known 

 "Coffee-leaf disease," which has caused so much havoc in Indian coffee 

 plantations. It is described as " forming bright orange powdery-looking 

 patches of variable size on the under surface of the leaf ; corresponding 

 areas on the upper surface of the leaf are of a sickly yellowish-green 

 colour." A Latin botanical description is given. — G. S. S. 



Orchids, Fertilisation Of. By G. T. Grignan (Bev. Hart. 

 Sept. 16, 1905, pp. 447-450; 2 woodcuts). — An interesting descrip- 

 tion of the reproductive organs of orchids and the best manner of 

 effecting crosses. — C. T. D. 



Ovularia, Supposed species of. By E. S. Salmon (Joum. Bot. 



506, pp. 41-44, 2/1905, plate; and 507, pp. 99-100, 3/1905). — A 

 demonstration that Crocisj)orium fallow, a fungus described by Bonorden 

 on the living leaves of peas, &c. ; Ovularia Clematidis, described by 

 Mr. Chittenden {Joum. B.H.S. xxviii. p. clxxvii.) on the flowers of 

 Clematis Jackmanni, Ovularia Ranunculi, and Oidium leucoconium, 

 are all four nothing more than the conidial stage of Erysiplw Polygoni, 

 the powdery mildew so common on peas, vetches, turnip, ranunculi, 

 &c. — G. S. B. 



" Pseonies." By George C. Watson. 4 ' Notes on the Cultiva- 

 tion of Pseonies." By B. I. Jackson (U.S.A. Hort. Soc. Mass. 

 Trans. 1904, pp. 134-157). — The first of these useful papers gives an 

 account of the development of the varieties of pa>ony from the original 

 forms, giving credit to workers both in America and England. The 



