538 Journal of Agricultural Research vo1.xv.no.io 



damped-o£f pine seedlings. His experiments were conducted in auto- 

 claved earth, with several pots both inoculated and controls, all being 

 under bell-jars. The controls remained free from disease. His species 

 of Fusarium, which he called F. pint, can not be positively identified 

 with any of the species at present recognized, from the data given in his 

 unpublished manuscript, which he kindly allowed the writer to examine. 

 A species of Nectria (later reported by Pollock ; 22) was associated with 

 the species of Fusarium. 



Gifford also carried out inoculation experiments with species of 

 Fusarium indicating its parasitism. His statement (9, p. 157) seems 

 reasonably conclusive, though the tables on the pages preceding and 

 following, presumably by reason of typographical errors, do not bear out 

 his statement as to the original disease freedom of his control pots. The 

 host with which he experimented was Scotch pine. The description of 

 the fungus which he gave indicates that it is not F. monilijorme, but does 

 not make it possible to refer it to any of the other recognized species. 

 While his inoculations were on autoclaved soil, the fungus was not given 

 quite such optimum conditions as in Spaulding's work, in that his inocu- 

 lum consisted of a spore suspension without any considerable amount 

 of nutrient medium accompanying. 



FUSARIUM MONIUPORME 



The species of Fusarium which the writers have found most virulent 

 among the four or more species which they have tested is F. monilijorme^ 

 This fungus is fortunately easy to distinguish from other species of the 

 genus, as it is understood to be the only species of Fusarium, in the 

 United States at least, which forms its microspores in chains. It is pre- 

 sumably not identical with the species and relatives of Fusarium de- 

 scribed as troublesome to coniferous seedlings in Europe, as none of the 

 European reports noted mentioned moniliform spores. The microspores 

 in the writers' cultures were ordinarily produced in delicate long un- 

 branched chains. Presumably on account of the delicacy of these spore 

 chains, the fungus seems especially well adapted for aerial dissemina- 

 tion. In planted petri-dish cultures numerous new colonies usually 

 start well in advance of the original colony, before the mycelium from 

 the original inoculation is able to cross the plate. In some cases, as in 

 Sheldon's cultures {23), microspores were agglomerated into heads, and 

 occasionally small heads of spores with chains arising from them have 

 been observed. The spores in the chains mea§ured in one case from a 

 prune-agar culture 2.2 to 3.1 by 4.8 to 6.3 /x. In another case from a 

 corn-meal agar culture 27 of the microspores ranged in length from 7.4 

 to 1 1 . 1 IX. Many of the cultures on the above media, but not all, developed 



1 All positive Fusarium ideotifications were made by Mr. C. W. Carpenter, Plant Pathologist of the 

 Hawaiian Experiment Station, based on comparisons with stock cultures named by Dr. W. H. Wollen- 

 weber, formerly of the Bureau of Plant Industry. 



