1893.] 



MICROSCOPICAL JOURNAL 



11 



tlttccl up to meet tlie requirements. The board of lej^ents, in 

 their report to the *;o\ernor an J lej^islatiire, have recommended 

 such a step, and in submitting their estimate tor tlie years KS93 

 and 1S94 asked for $5,ocx) for this purpose and the equipment 

 of the hiboratory with the necess:ir\- apparatus, etc. 



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

 has cleared up the uncertainty which existed re<;ar(Hn<j the fun- 

 gus Crrcospora apii of I'resenius. He says in N. ^'. Agr. 

 Exp. Bull.. No. 49 : 



Like AXCcrcosporic^ the vegetive threads of this fungus usually 

 grow largely in the interior of the leaf, aiul when the nutriment 

 at the all'ected 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 Cercospora 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, /. c, the base or end at tiie point 

 of attachment with the hyphic is greater 

 in diameter than the distal extremity. 

 The conidium in situ at the end of the 

 hypha, r, shows this character well. 

 The free or abjointed conidia nearlv 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 liypha 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'hyphit. 



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 hypha- and their 

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



