DISEASES OF PL \ N I S. 875 



with lime, since thai time there has been no further attack upon the cauliflower in 

 this house. 



Intumescences formed as a result of chemical stimulation, II on Si eirbnk 

 | Mo. Bot. Gard. Ann. HpL, 16 1905), pp. 125 l ;.v. ph. ; i. \- mentioned in another 

 place, while spraying cauliflowers for the crucifer mildew, Peronospora parasitica, with 

 ammonium copper carbonate certain injuries were noted on the leaves. These were 

 more abundant on the lower surface than on the upper, and consisted of various 

 irregular swellings and distortions. The experiments carried on showed thai similar 

 intumescences were produced by means of weak solutions "i' other copper salts, and 

 thai they were entirely independenl of the Boil or atmospheric conditions. 



They are considered a result of the stimulating activity of chemical poisons sprayed 

 apon the leaf in weak solutions. This activity is probably due to the formation of 

 compounds within the cells, either in combination with the copper salts or com- 

 pounds wh it'll arc a result of the stimulus observed i»> the spray. This is evidenced 

 by the presenceof large amounts of oxidizing enzyms as a result of extra stimulus 

 excited by the salts sprayed upon the leaf surface. A bibliography of in papers is 

 appended to the report. 



A disease of cauliflower and cabbage caused by Sclerotinia, G. <■. Hedg- 

 cock (Mo. Bot. Gard. Ann. Rpt, 16(1905), pp. 149-152, pis. 8, fig, l). — For Beveral 

 years a disease of cauliflower and cabbage lias been observed at t lie Missouri Botanical 

 Garden and in the vicinity, which is manifested by a dark rol of the plant- accompa- 

 nied by numerous tiny black specks. 



The disease was at first thought to be a form of the bacterial rot, but a more careful 

 examination showed that the interior of the cauliflower stems was uniformly filled 

 with mycelium of the fungus which was identified as Sclerotinia libertiana. The rol 

 produced by this fungus is dm ire watery and the diseased tissues are not so dark as in 

 the case of the bacterial rot of cruciferous plants. 



Inoculation with the ascospores from the apotheciaand the mycelium from pure 

 cultures produced the typical rot of the cauliflower. Control plants, wounded hut not 

 inoculated at the same time, remained tree from the disease. 



A disease of cultivated agaves, <i. (i. Hedgcoce (Mo. />'<</. Gard. .Inn. /,'/-/.. 16 

 i 1905), pp. 158-156, pis. 8). — A number of small plants of Agavi utahensis were potted 

 during the spring of 1904 and placed in the Large collection of the Missouri Botanical 

 Garden. In a short time many of the plants were found dying from a disease w hich 

 first attacked the older leaves. 



A study of the fungus showed thai it belonged to the species Colletotrichum and 

 inoculation experiments showed that it could he readily transferred. The disease 

 has a striking appearance, the tissues penetrated by the mycelium showing either a 

 circular or elliptical spot which at first is dark in col of. changing as the tissues die, t . . 

 brown or gray. Dnder humid conditions the leaves turn brown and rol rapidly. 



Bordeaux mixture of the ordinary formula proved beneficial in preventing the 

 Bpread of the fungus to adjacent plants. 



Fungus galls, II. von Guttenberg | Reitragt zur physiologischen Anatomu </<r PUz- 

 fjatten. Leipsic: WUhelm Engelmann, 1905, pp. 7<>, pis. i; rev. in Natun [London], 72 

 (1905), No. 1867, pp. 389, 340). In this work the author describes the effects caused 

 by 5 different fungi on as many hosl plants. 



Both fungi and hosts belong to widely separate families and include Albugo on 



shepherd's purse, Exoascus on alders, [Jstilag i maize. Puccinia on Adoxa, and 



Exobasidium on Rhododendron. The author attempts to explain the various ana- 

 tomical changes occurring in the fungus galls from a physiological standpoint. These 

 changes, in his opinion, are mostly due to a change of function which the tissues 

 assume under the influence of the parasite for it- exclusive benefit. 



In the main, the ant hoi- con si dels the fungus a- controlling the development of the 

 host plant, hut in the case of the corn smut it is shown that where the intracellular 



