1916] DISEASES OF PLANTS. 459 



A disease of Mirabilis jalapa inherited according to Mendel's law, C. Cor- 

 RENS (Jahrb. Wiss. Bot. [Pringsheim'], 56 {1915), Pfeffcr-Festschr., pp. 585-616, 

 pi. 1, figs. 11). — Attention is called to a phenomenon consisting of a mottling, 

 slight pitting, and partial rolling of the leaves in M. jalapa. This is stated to 

 be due to a sort of degeneration of certain palisade and overlying epidermal 

 cells with enlargement of cells in neighboring areas, the lower leaf surface 

 remaining relatively unchanged. The phenomenon appears to be inherited ac- 

 cording to the Mendelian formula and may possibly throw some light on the 

 nature and mode of inheritance of characters. 



Bark scraping and bark affections, A. Shabples {Agr. Bui. Fed. Malay 

 States, 3 (1915), No. 11, pp. 420-^25) .—It is stated that, while the canker of 

 rubber trees caused by Phytophthora faberi is unknown in Malaya, what is sup- 

 posedly the first bark affection known in this region has recently appeared in 

 the form of a slow rotting of the bark, over which numerous saprophytic fungi 

 were growing. The bark became waterlogged and subject to attack by borers, 

 necessitating the removal of the tree. 



It appeared probable that the fundamental cause of the trouble was a 

 method of scraping supposed to stimulate the tree to an increased flow of 

 latex. Tests made under controlled conditions are said to have shown that 

 the removal of the outer corky layers increased the susceptibilty of the tree 

 to attack by fungi and insects. This increase of susceptibility was less if the 

 green cork cambium was left intact, so that this is apparently the protective 

 layer that is the most important in this connection, and not the lactiferous layer, 

 as formerly supposed. Further discussion is given of the conditions and phases 

 of attack by insects and fungi, and the interrelations of the two classes of 

 parasitism. 



It is considered that bark scraping of any description should be carried out 

 with discretion, also that until more positive knowledge is obtained as to the 

 function of the latex in the economy of the tree, a conservative attitude is 

 desirable in connection with methods for artificially increasing the flow of 

 latex. It is considered as a still unsettled problem of prime importance to the 

 future of the rubber industry whether latex is a primary product, the with- 

 drawal of which means Increased activity for its replacement, or a secondary 

 or waste product. 



Bordeau mixture as a spray for rubber trees, A. Sharples (Agr. Bui. Fed. 

 Malay States, 3 {1915), No. 12, pp. W, hk^). — During experiments carried out 

 in 1914 as already noted (E. S. R., 33, p. 151) the effects of Bordeaux mixture 

 on the rubber obtained during its use were noted, and these are briefly de- 

 scribed in this article. It is asserted that there is little danger in using Bor- 

 deaux mixture as a spray against the attacks of fungi on rubber trees, but 

 that trees in bearing should be rested for two or three days after such appli- 

 cation. 



[On tbe occurrence of Coniophora cerebella in the woods], V. Martens 

 {Mat. Mikol. i Fitopatol. Ross., 1 {1915), No. 3, pp. 52-56, figs. 7).— The author 

 observed a peculiar rot of fir trees in northern Russia, in the regions of Volo- 

 goda and Archangel. From the diseased areas adjacent to the healthy tissue, 

 he isolated a fungus which in certain morphological characters resembles very 

 closely C. cerebella. If further studies confirm this tentative conclusion, this, 

 it is said, will be the first report on the occurrence of this fungus on living 

 trees in the woods. 



Mistletoe injury to conifers in the Northwest, J. R. Weir ( U. S. Dept. Agr. 

 Bui. 360 {1916), pp. 39, pis. 4, figs. 27). — Accoixling to the author, Larix occi- 

 dentalis, Pinns ponderosa, P. contoria, and Pseudotsuga taxifolia are subject 

 to attacks of Razoumofskya laricis, R. campylopoda, R. americana, and R. 



