204 Journal of Agricultural Research voi. v,no. s 



A. SECTION MARTIELLA 



[Species in this section are F. solani (Mart.) Sacc., F. martti App. and Wollenw., F. eumartii, n. sp., F. 

 coeruleum (Lib.) Sacc, and F. radicicola Wollenw.] 



1. Fusarium solani (Mart.) Sacc. (i, p. 77). 



Conidia normally triseptate (PI. XIV, fig. 3) up to 100 per cent, occun-ing in 

 pionnotes and sporodochia,^ averaging 30 to 40 by 5 to 6ju. Limits of normal tri- 

 septate conidia: 25 to 45 by 4.5 to 6.5^. Seldom 2 and 4, exceptionally i and 5 

 septate (limits: i-septate, 15 by 4;u minimum; 5-septate, 59 by 6.5^ maximum; greatest 

 width, 7m; highest septation, 7.) Conidial mass brownish white, becoming brown in 

 age; often greenish as a result of infiltration with greenish blue pigment from the 

 plectenchymatic mycelium. Chlamydospores terminal, intercalary, and conidial; 

 unicellular, round or pear-shaped, 8.5 by 8 ju; 2-celled with constriction at cross wall, 

 12 by 7.7SM; smooth, rarely in chains or clumps. 



Habitat. — On decaying tubers and roots of plants and in the soil. Isolated from 

 species of Solanum, Citrullus, Cucumis, Cuciubita, Lycopersicon, Pinus, Hibiscus, 

 Avena, Zea, Triticum, Panax, Citrus, Pelargonium. Collected by various investi- 

 gators and identified by WoUenweber and Carpenter. 



F. solani (sensu strict.) is regarded as a saprophyte, but apparently 

 it acts as a weak w^ound parasite under exceptionally favorable con- 

 ditions. 



2. Fusarium coerixleum (Lib.) Sacc. (i, p. 90). 



Conidia normally triseptate (PI. XIV, fig. 5), averaging 30 to 40 by 4.5 to 5.5;* 

 (limits of normal triseptate conidia: 23 to 47 by 4.25 to 6^); seldom 4 and 5 septate 

 (limits: triseptate, 23 by 4.25/n minimum; 7-septate, 58 by 5.75M maximum). Coni- 

 dial mass brownish white and yellow ocher to reddish ocher. Plectenchymatic stroma 

 chiefly violet to indigo blue and bluish black; by infiltration with the latter color 

 the conidial masses may become bluish green, as in other species of the section Mar- 

 tiella. F. coeruleum is the only species of the section having reddish ocher conidial 

 masses. Chlamydospores as in other species of the section. 



Habitat. — On tubers of Solanum tuberosum. Established as a cause of tuber rot 

 in this coimtry and in Europe by WoUenweber (20, p. 44). Determined by Dr. 

 WoUenweber and the writer in material from the following localities: Ottawa, Canada; 

 Houlton, Me.; Rhinebeck, N. Y. ; Fredericksburg, Md.; Norfolk, Va. ; Parkersbiu-g, 

 W. Va.; Doimybrook, N. Dak.; Idaho Falls, Idaho; Potlatch, Wash.; and several 

 places in Oregon. 



3. Fusarium eumartii, n. sp. 



F. eumartii isolated from the Pennsylvania dry-rot agrees with Appel and WoUen- 

 weber's (i, p. 78-84) diagnosis of F. martii except in certain details of the conidia. 

 The latter in the new species are higher septate and have a somewhat larger average 

 size (PI. XIV, fig. 4). Normally 4 to 6 septate, averaging 54 to 75 by 5.5 to 6.6m 

 (limits: 50 to 80 by 5 to 7.2^). Largest conidia 85 by 7.2M (7 and 8 septate). Per- 

 centages of variously septate conidia, average sizes and limits as found in a lo-day- 

 old pionnotes on Melilotus alba and in a 15-day-old pionnotes on cotton are given in 

 Table VII. 



• For definition of these terms see WoUenweber, H. W. (20, p. 24). 



