mSEARKS OF PLANTS. 647 



cultnros of the fimt^us aitplicd to lottufe plants. Wlicro the spores wcro placed 

 directly upon uiiiiijiired leaves no infection took place, but wherever the leaves 

 were wounded, either by teariuf; or burning with a hot platinum needle, infec- 

 tion ensued. 



While carryinj; on those experiments, the author noted tliat the plants on 

 w'jich the leaves had bet:un to turn yellow were readily infected. Subse- 

 quent investi^'ations, in which plants were kept for T* days in the dark and 

 si)ores placed upon them when the leaves were beginning to show signs of 

 yellowing, showed that the fungus was readily introduced into otherwise sound 

 tissues. 



Another experiment was carried on in which lettuce was grown in cultures 

 from which some of the supposetlly essential organic constituents were omitted. 

 After 6 weeks' growth in such cultures, the plants were inoculated by placing 

 Botrytis spores ujjon the leaves, but without any infections. 



In conclusion the author states that " whatever may be the causes at work 

 in the living cell which confer immunity or iiredisi)osition on the species of host 

 plant, or which confer virulence or ini])otence on the spore, they lie deeper than 

 nutrition." 



The physiology and development of some anthracnoses, C. W. Edgerton 

 {Bat. Gaz., J,5 {190S), \o. «, pp. 36r-J,08, pi. /, fiffs. 17).— A study of some 

 anthracnoses has been carried on to determine the perfect stage of as many 

 forms as possible, to ascertain whether the forms of Gloeosporium found on the 

 apple represent a single species or more than one, and to learn whether species 

 of (jkeos|iorium may be distinguished by cultural methods, in the study the 

 author investigated the anthracnoses of about 80 different host plants from 

 50 or more sotu-ces. The genera that are known to be connecteil with anthrac- 

 noses are Gnomonia, Glomerella, and Psendopeziza. 



From an ec-onomic standpoint, the most important species belong to the 

 Glomerella type, which is distinctly separated from the other types of anthrac- 

 noses both by its perfect and imperfect stages. There seem to be a large 

 number of closely related forms that are extremely variable. Furthermore, 

 many forms vary under artificial cultivation and doubtless also under natural 

 conditions. Some of these forms seem to be similar enough to be considennl 

 the same, while others are dissimilar enough to be classed as distinct species. 



In relation to the forms occurring on the apple, there seem to be two distinct 

 forms of anthracnose separated by thermal lines. That occurring in the 

 southern part of the country differs in tlie presence of perithecia, a slightly 

 different acervulus, and entirely different cultural characters. From his in- 

 vestigations the author is led to believe that too much dci)endence should not 

 be placed on cultural characters for the determination of the species. 



On the specialization of a form of Sphaerotheca humuli, .T. A. Steinkr 

 (Ciiilhl. ISiiht. I'/r. I. >. Ah(., 21 HHOS), \i>. 22-J,i, pp. (n7-7.U!, pi. /, /?f/.s'. 3).— 

 Experiments by the author showe<l that there is a bi<iIogical form of »s'. humuli 

 occurring on various s|)ecies of Alchemilla, and he describes it under the name 

 of S. humuli alchemilla: His experiments showed that there is little difference 

 betwe<'n infection by ascospores and by conidia of the fungus, and that of the 

 form described several races exist capable of infin-tiug some species of Alche- 

 milla and not others. 



The Sporotrichum bud rot of carnations and the silver top of June grass. 

 F. C.Stewart and II. E. IIoixiKiss (.Vcjc York- state Sl<i. Tccli. lhil.7, pp. S,i-1 1!), 

 plH. fj).— The carnation bud rot described l)y the authors is said to be identical 

 with that discussed in I'.ullefin l(l.'i of the Nebraska Station ( E. S. K., 10, 

 p. ><.")). It is known to occur in several gretMihou.ses in New York, Illinois, 

 and .Nebraska, but it is not belleveti to be of great economic Importance. 



