DISEASES OF PLANTS. 651 



nieut of the intercellular system. The symbiosis of the host cell uiu\ the haiis- 

 toria iu a cell goes on peacefully for a time, but finally they become separated 

 by a plasmoderm. It is possible by plasmolyzing the cells to separate them quite 

 distinctly. The leaf cells do not show the characteristic signs of iX)isoning by 

 the infection until just before their death. 



An extensive bibliography is appended. 



A leaf disease of Hevea in Surinam, J. Kuyper (Rcc. Trav. Bot, l^eerland., 

 S (1911), Xo. 3-4, pp. 371-3S0, pis. 2).— A leaf disease of II. brasiliensis and 

 H. guyanensis due to Fusicladium rnacrosporum n. sp. is described. Three 

 stages of the disease are mentioned. The first is on the young leaves, which 

 show olive or dark green spots on plants in the seed bed. In the second stage 

 black fruiting bodies appear on the older leaves of nursery stock and of larger 

 trees. The third form attacks the petioles and stems of more mature plants. 

 The fungus appears endemic, occurring throughout Surinam in plantations as 

 well as on wild trees. 



Spraying with Bordeaux mixture, it is believed, would control the fungus. 



The chestnut tree disease, M. Manson {Science, n. ser:, 35 {1912), No. 894, 

 pp. 269, 270). — On account of the destruction of the chestnut by the so-called 

 chestnut disease, the author calls attention to the desirability of testing the 

 giant chinquapin {Castanopsis chrysophiUa) of the Pacific States for planting 

 in the Southern States. This plant is said to occur in 2 forms, one a large 

 tree, the other a shrub, and the author believes that the tree form could be 

 used to reforest the Eastern States devastated by the chestnut tree disease and 

 that it would probably stand the eastern conditions from Maryland south. 



Pine leaf cast, Haack {Ztschr. Forst u. Jagdio., 43 {1911), Nos. 4, pp. 329- 

 357, pi. 1; 5, pp. 402-423; 6, pp. 481-505, fig. 1; ais. in Hedwigia, 51 (1911), 

 No. 3, BeiM., pp. 202, 203). — The author gives an extended discussion of this 

 widespread and dangerous disease of pines, ascribed to the fungus Lophoder- 

 mium pinastri. 



Pines of all ages show attack in varying degrees. Young pines are usually 

 killed by loss of their leaves, but after attaining an age of 8 or 10 years they 

 usually appear to be able to withstand the injuries. Infection occurs not 

 through conidia but through the spores, which are freed more rapidly in damp 

 weather and are carried by wind and water to considerable distances. The 

 needles which fall in early spring become a new source of infection in summer 

 and autumn. The parasitic mycelium seems i:)referably to live intercellularly. 



Spraying with a weak solution of copper sulphate is recommended, care- 

 fully applied, when the apothecia first open in spring and summer. Grass 

 should be kept out of the way of spraying operations, and infected portions 

 of the pine trees should be removed at once. 



Leaf cast and nativity of the pine, H. Mayr {Forstio. Centbl., n. ser., 33 

 (1911), No. 1, pp. 1-14; al)S. in Ilcdivigia, 51 (1911), No. 3, Beibl, p. 204).— 

 The author gives his views, as the result of his studies on the pines of Europe, 

 regarding the resistance offered to the fungus (Lophodermium- pinastri) causing 

 leaf cast. The Norway pine is asserted to suffer least and the southern and 

 southeastern pines most from this disease, while the pines of the Alps and 

 Scotland stand between these in resistance. 



Accordingly, the author recommends breeding from the Norway variety as a 

 means of securing a hardy stock for German culture. He mentions the fact 

 that his views are opposed by various other investigators. 



Notes on Cronartiuni ribicola, P. Spaulding (Science, n. ser., 35 (1912), No. 

 891, pp. 146, 147). — Attention is called to a number of points that have been 

 worked out in connection with the life history of this fungus during the past 

 year. A coarse yellow mottling of pine needles and of the bark on the twigs 



