Fusaria of Potatoes 



127 



On hard lima-bean agar, culture four days old: 

 Conidia: 0-septate, 40 per cent 



1-septate, 60 per cent, 10.2 x 3 (9-11 x 2.8-3.8)/* 



On nutrient agar, culture six days old: 

 Conidia: 0-septate, 10 per cent 



1-septate, 90 per cent, 11.4 x 2.8 (8.7- 

 13 x 2.4-3.5) /* 



Average of the above measurements: 

 Conidia: 0-septate, 32 per cent, 7 x 2.2/* 



1-septate, 68 per cent, 10.2 x 2.8/* 



The size of the spores of F. affine as given by 

 Saccardo (10-15 x 4/*) differs somewhat from the 

 above, but the description otherwise is so much the 

 same that the organisms can be considered iden- 

 tical. 



2. Fusarium dimerum Penz. (Figs. 1e and 3) 



Penzig, O., Michelia 2:484. 1882. Saccardo, 

 Syll. Fung. 4:704. 1886. Lindau, Rab. Krypt. 

 Fl. Pilze 9:566. 1910. Appel and Wollenweber, 

 Arb. K. biol. Anst. Land- u. Forstw. 8:37, text 

 figs. 2 and 4. 1910. 



Conidia lunar, somewhat pedicellate, typically 

 1-septate, 13 x 3.3 (12.5-13.5 x 3.3-3.4)/*, often 

 also 0-septate, rarely 2- or 3-septate, borne singly 

 on the mycelium or forming a more or less contin- 

 uous slimy layer, from hyaline to cinnamon-buff 

 on glucose agar; mycelium from hyaline to about 

 the color of the conidial masses; chlamydospores 

 intercalary, in mycelium. 



Hab. On tubers and stems of Solanum tuberosum in Germany and in 

 Minnesota (U. S. A.), and on fruits of Citrus medica in Italy. 



The fungus is easily distinguished from all the other Fusaria by its lunar, 

 minute, 1-septate conidia. It was isolated by the author only once, 

 from a superficial dry rot of potato tuber received from St. Paul, Minnesota. 



Fig. 3. — Fusarium di- 

 merum. a, Pseudopion- 

 notal conidia from 70- 

 days-old culture; B, 

 conidiophore, c, pseu- 

 dopionnotal conidia, 

 from 19-days-old cul- 

 ture on slightly acidified 

 hard potato agar; o, 

 conidiophore from 70- 

 days-old culture on po- 

 tato stem plug; E, co- 

 nidia, f, conidiophore, 

 from 43-days-old culture 

 on hard lima-bean agar 

 with 2 per cent glucose; 

 G, chlamydospores; H, 

 conidiophores, i, co- 

 nidia, from 21 -days-old 

 culture on hard lima- 

 bean agar 



