DISEASES OF PLANTS. 961 



A new form of seed-sampling- apparatus, F. Todaro (Staz. Sper. Agr. Jtal., 3S 

 {I'.iOo), X<>. r,^ jij). 4:i:.'-494, fig. 1). — A description i.s given of the form of apparatus 

 devised liy tlie author for sampling clover and similar seeds. 



Troublesome weeds, T. W. Kihk {Ncir Zealand Dept. Agr. Rpt. 1900, pp. 308-312, 

 figs. 3). — Illustrated notes are given on cape weed {Cryptostemma calendulacea) , 

 cocklebur or Bathurst bur {Xanthium npinosuin), and Strathmore weed {Finielea spp. ). 

 The latter are reported as poisonous to horses. 



Combating: weeds by means of chemical agents, J. Graftiau {L'Ing. Agr. 

 (u'lnUoiLc, JO {WOO), So. 6, pp. 413-4-^8). — A review is given of experiments which 

 have been conducted for the destruction of weeds and mosses by means oi various 

 chemical solutions. The conclusions drawn by the author are that it is possible to 

 destroy many noxious weeds by spraying with solutions of copper sulphate or of iron 

 sulphate. It is stated that dodder can be successfully combated by spraying with a 

 3 to 5 per cent solution of copper sulphate. 



DISEASES OF PLANTS. 



Specimens received for examination by the bacteriological 

 laboratory, F. T. Bioletti {(Ulifor/iJ(/ iSfa. Rpt. lSf)S, pp- l^'K ^^h-, 

 p(j. I). — Miscellaneous notes are given on many specimens and samples 

 which were sent to the hacteriolog-ical laboratory for examination. 

 Among- some of the more important facts brought out by the examina- 

 tion was the occurrence of leaf spot on violet leaves due to Cercof^pova 

 ri()]((' and PJiyllo.^ticta iiiolxe. ¥ov the prevention of these diseases spray- 

 ing plants with weak Bordeaux mixture at intervals of ten days is recom- 

 mended. Specimens of diseased grapevines were sent to the author, 

 in whi(-h the main roots were dead and a few small lateral ones remained 

 living. The triuik and branches showed no evidence of disease except 

 in the short growth of the previous year. The roots were covered with 

 a fungus beneath the bark which the author considers the mycelium of 

 some toadstool fungus. The same disease is known to occur in oak 

 trees, and no cure is known when the plant is once thoroughly invaded 

 bv it. Preventive measures, such as digging up and burning the 

 diseased parts, are recommended. Brief notes are given on a number 

 of other diseases which are of minor importance. 



Concentric spore spots, B. 1). Halsted {Seience., n. ser.., 12 (1900), 

 j\va JOo, pp. .T,sYy, -7rS7). — The author describes the method by which 

 the parasitic fungi reach the surface of their host plants for the distri- 

 bution of their aerial spores. The most of them have two forms, one 

 in which the exit is made through stomata, the second type eu)bracing 

 those fungi which underlie the epidermis, rupturing it. To the first 

 type belong the Peronosporas, Cercosporas, Ramularias, and Macros- 

 poriums; while to the second type belong the Cystopus, Glcjeosporium, 

 and many of the rusts. Those fungi that produce their spores through 

 the stomata have their disti-ibution definitely limited. The second type 

 of spore production results in a rupture of the epidermis, and inunedi- 



