1893.] 



MICKOSCOPICAL JOURNAL. 



115 



fitted up to meet the requirements. The board of regents, in 

 their report to the governor and legislature, have recommended 

 such a step, and in submitting their estimate for the years 1S93 

 and 1S94 asked for $5,000 for this purpose and;] the equipment 

 of the laboratorv with the necessary apparatus, etc. 



On the Fungus of Celery Blight.— Prof. G. F. Atkinson 

 has cleared up the uncertainty which existed regarding the fun- 

 gus Ccrcospora apii of Fresenius. He says in N. Y. Agr. 

 Exp. Bull., No. 49: 



Like all Cercospora:^ the vegetive threads of this fungus usually 

 grow largely in the interior of the" leaf, and when the nutriment 

 at the atiected spot is nearly exhausted clusters of fruiting 

 threads arise from the vegetive ones and, issuing from a stoma 

 of the leaf, bear elongated spores at their ends. Two clusters of 

 the fruiting threads of Cercosporo Apii are shown at a and b., 

 while c represents a single fruiting thread with a spore still 

 attached, and free spores are shown at d 

 and e. 



The form of the conidia is given^as ob- 

 clavate, i. e., the base or end at the point 

 of attachment with the hyphte is greater 

 in diameter than the distal extremity. 

 The conidium ifi situ at the end of the 

 hypha, r, shows this character well. 

 The free or abjointed conidia nearly al- 

 ways present a well-defined scar at the 

 larger end as shown in d and e. This 

 scar indicates the place of attachment to 

 the hypha, the corresponding scar on the 

 hypha being at the end or at one of the 

 geniculations as^^shown in a and b. The 

 explanation of several scars appearing on 

 a single hypha is that after a conidium is 

 abjointed from the end, the hypha then 

 grows out at one side of the scar and 

 bears another conidium at the end, and 

 so on. These scars at the base of the 

 conidia enable one to determine their 

 form even when they are not attached to 

 their parent'hyphge. 



Under normal conditions the fungus is 

 confined to well-defined spots on the leaf 

 with an irregular, slightly raised border. 

 During excessively wet weather, as the 

 leaf tissue is dying, it may spread to por- 

 tions of the leaf where the spots are not 

 so well defined. Such conditions also 

 induce a much longer growth of the tufts of hyphte and their 

 conidia ; a and d represent such forms in comparison with b and 



