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Pomona College Journal op Economic Hotany. 



General culture characters. No disagreeable odor developed in any of 

 the cultures; whenever any odor could be detected, it was of a pleasant 

 rather than of a disagreeable nature. Some coloration appeared in all cul- 

 tures kept in the liglit. All cultures formed spores; they were most al)un- 

 dant in old cultures or in cultures with little available food. Very few 

 chlamydospores formed in the lla.sk cultures. 



COMPARISON OF THE CARNATION AND POTATO STRAINS 

 The description of the cultural characters for the different media have 

 shown that the carnation Fusarium is a much more vigorous grower than 

 the potato Fusarium, producing a stronger stroma, a higher aerial mycelium 

 and also in producing a distinctive yellow color differing from any which 

 appeared in the potato Fu.sarium cultures. A morphological difference 

 occurs in the spores. The carnation strains develop very few conidia which 

 could be classified as micrceonidia. The four- to six-celled curved macro- 

 conidia is the type universjilly found. On the other hand the potato strains 

 develop oblong to cylindrical microconidia in great al)undance, and compara- 

 tively few of the true Fusarium macroconidia. The potato and carnation 

 strains form chlamydospores differing greatly in appearance. The carna- 

 tion strains form large yellowish brown chlamydospores 10 u.-20 u. in 

 diameter; some are spherical, others are oblong and divided by transverse 

 walls. All contain very large granules of protoplasm. The potato strains 

 form light brown chlamydospores, most of which are .spherical and only 

 6 U.-12 u. in diameter. They are filled with much smaUer granules of 

 protoplasm and all are one-celled. (Plate V. Figures 5 and 11, a, b, c.) 



The composition of the different cultural media used in the studies of 

 the various species of Fusarium fungi are given in the following descriptions. 



Beef extract bouillon (Ml). This medium consisted of the following 

 materials : 



These ingredients were dissolved in nearly the full amount of water, 

 boiled a few minutes, enough distilled water added to make the total 500 

 c. c, and filtered twice through absorbent cotton. 



Sugar beet agar (M2). A large, sound sugar beet was thoroughly 

 scrubbed, washed in distilled water, pared, and cut up in fine pieces. To 

 400 grams of beet was added 1000 c. c. of distilled w^ater, and the whole was 

 heated until the pieces of beet could be easily crushed into a pulp, then 

 filtered through a clean towel. Four grams of thread agar were dissolved 

 and added to the beet liquid with enough distilled water to bring the total 

 up to 800 c. c. The medium was then filtered through absorbent cotton, 



CULTURE MEDIA USED 



Peptone 



Beef extract .... 

 Common salt .. 

 Distilled water 



. 1% — 5 grams 

 .0.5% — 2.5 grams 

 .0.5% — 2.5 grams 

 .500 c. c. 



