Apbil 22, 1910] 



SCIENCE 



639 



thecia of a Nectria. None of them grew upon the 

 dead seedlings but directly on the soil. There was 

 no stroma and no subiculum, though some hyphae 

 might be found radiating from the perithecla. 

 The experiment was repeated, using infected soil 

 and again the peritheeia appeared in a little more 

 than two months. The attempts to grow the 

 ascospores were unsuccessful, perhaps chiefly be- 

 cause of the great numbers of bacteria which 

 developed. Peritheeia appeared upon two control 

 pots out of fourteen, as well as upon all fourteen 

 of the infected pots. The control pots stood 

 beside the inoculated pots on the bench in the 

 greenhouse. At the present time the connection 

 between the Neotria and Fusarium Pmi is not 

 absolutely established, but seems very probable. 



A Barley Disease: L. H. Pammel, Chablotte M. 



King and A. L. Bakke. 



During the past season a parasitic fungus made 

 its appearance upon barley, during the early part 

 of July. This new disease manifests itself in the 

 form of brownish circular or somewhat elongated 

 dark-colored spots. The leaves soon become brown. 

 The long cylindrical dark brown spores have from 

 seven to ten divisions and measure 105-130 /i X 

 15-20/1*. Cultures were made and inoculation 

 experiments demonstrated that the fungus was 

 parasitic upon barley but not upon corn. Hence 

 the disease is diflferent from the Helminthosporium 

 teres found on corn and the H. turcicum. The 

 spots of B. graminum consist of longitudinal striae 

 of yellowish green color; the spores of this species 

 measure 75-95 m X 15-17/*. 



Notes on some Diseases of Coniferous Nursery 



Stock: Cabl Haetley. 



Damping off of coniferous seedlings is com- 

 monly caused in this country by Fusarium, and 

 favored by moist conditions. In a Nebraska nur- 

 sery Rhizootonia sp. and a fungus which appears 

 to be Pythium DeBaryanum, have been found in 

 diseased seedlings, and inoculations indicate the 

 ability of both to kill germinating pine seeds and 

 to cause damping off. A great deal of damping 

 off occurred under very dry conditions. A para- 

 sitic leaf blight on older seedlings was found to 

 be favored by crowding and dry soil, and pre- 

 vented by the use of shade frames. 



Pomes annosus and Two Species of Gymno- 

 sporangium, on Juniperus virginiana: Cabl 

 Habtlet. 



Fomes armosus, a very dangerous root parasite 

 in European coniferous forests, has been reported 

 by Spaulding as parasitic on Pinus Strobus and 



P. rigida in New England. It is now found to 

 cause the death of Juniperus virginiana, and 

 apparently also of Firms tceda, in Delaware. 



Gymnosporangium germinale, and an unde- 

 scribed Gymnosporangium which occurs on bark 

 of all ages, have been found in connection with the 

 gradual death of red cedars in Virginia and Mary- 

 laud, and by Spaulding in Connecticut. The latter 

 fungus was probably the chief cause of the disease. 

 Origin of Hetercecism in the Rusts: Edgab W. 



Olive. 



Accepting the view that the heteroscious aecid- 

 ium cup forms of rusts were the last in evolu- 

 tionary history and that their ancestral forms 

 were autcecious and similar to the present lepto- 

 and micro-rusts, the paper seeks to contribute 

 toward the question of primary and secondary 

 hosts. 



Three arguments are presented toward proof 

 that the present gametophytic, or secidial, host was 

 the primary host which bore the autflecious an- 

 cestor. It is claimed that from a cytological 

 standpoint the main proof is furnished. The 

 stage of the sexual cell fusions is regarded as at 

 least equal in importance to the final stage of 

 teleutospore formation, if not indeed as the most 

 invigorating phase of the whole life history. From 

 a cytological standpoint it seems inconceivable 

 that the jump to an absolutely new host could 

 have been made by the uninueleated basidiospores 

 resulting from the germination of the teleuto- 

 spores; since the jump would be thus made at a 

 time when the reduction occurs which changes the 

 fungus from the presumably more vigorous diploid 

 generation back to the primitive haploid genera- 

 tion. It seems, rather, more reasonable to expect 

 that the double nucleated secidiospores, endowed 

 with the greatest amount of vitality from the 

 conjugation which has just preceded them, would 

 be thus much better adapted to make the jump 

 to another distinct host. Reasoning from analogy, 

 we should naturally be led to expect at this stage, 

 following the sexual fusions, new possibilities of 

 development and consequently new possibilities for 

 infection of foreign protoplasm. 



Such forms as the morphological species of 

 Puccinia graminis are regarded as furnishing an- 

 other point in favor of this theory. The fewness 

 and evident close relationship of the gametophytic 

 hosts argues strongly that the barberry was the 

 original host in this case and that the vigorous 

 secidiospores were able in their jump over to a 

 secondary host to infect many sorts of grasses. 

 The third and final point brought out in favor 



