FusARiA OF Potatoes 



203 



Microconidia always greatly in excess; ma- 

 croconidia ranging from rare to several per cent 

 of the total number of conidia, mostly nearly 

 straight, sometimes slightly curved, tj^pically 

 3-septate, 36x3.85 (25-40 x 3.2-4) yu; aerial 

 mycelium usually well developed, from white 

 to a tint of olive-buff; substratum, on potato 

 agar rich in glucose, colorless at first, then 

 from russet vinaceous to deep brownish 

 vinaceous; no sporodochia; no pseudopion- 

 notes; no sclerotia. Not the same as F. 

 oxysporum. 



Hab. Roots and tubers of Solanaceae, also 

 on various other hosts and in soil, in Europe 

 and North America. 



The organism was not isolated by the writer. 

 The original culture was obtained from the 

 Centralbureau der Association Internationale 



Fig. 29. — Fusarium orthoceras. 

 A, Conidia from 18-day s-old 

 culture on slightly acidified 

 hard potato agar; b, conidia 

 from 26-days-old culture on 

 potato tuber plug; c, conidia 

 from 15 -days-old culture on 

 hard lima-bean agar with 2 per 

 cent glucose; d, chlamydospores 

 from 18-days-old culture on 

 slightly acidified hard potato 

 agar; e, conidia, some in a 

 ball, with conidiophore of com- 

 mon type, from 30-days-old 

 culture on corn agar; f, 

 chlamydospores from 53-days- 

 old culture on potato tuber plug 



des Botanistes, Amster- 

 dam, Holland, and was 

 studied in conjunction 

 with the other Fusaria. 

 The above description 

 is in the main the same 

 as that given by Wol- 

 lenweber. 



Fig. 30. — Fusarium angustum. a, Pseudopionnotal conidia 

 from 4-days-old culture on slightly acidified hard potato 

 agar; b, conidiophores from surface of the exposed substratum 

 from 25-days-old culture on corn agar; c, pseudopionnotal 

 conidia from 9-days-old culture on hard lima-bean agar with 

 2 per cent glucose; d, pseudopionnotal conidia from 8-days- 

 old culture on hard lima-bean agar; e, microconida from 

 aerial mycelium; f, chlamydospores from 74-doys-old red 

 raspberry cane plug; G, conidiophores from 9-days-old cid- 

 ture on hard lima-bean agar with 2 per cent glucose 



34. Fusarium angus- 

 tum n. sp. (Figs. 1, Gi 

 and Hi, and 30) 



Conidia graduall}- 

 pointed toward apex, 

 from slightly curved to 

 nearly straight or an- 



