121 



larly in a e, b e, c e, d e, and e e' is significant. If plate e be left 

 out of consideration, the others agree reasonably well, with differences 

 greater than the probable error in six out of ten cases, the difference being 

 but slightly above the probable error in two cases, about twice the probable 

 error in two cases; and about thrice that, in two cases, the largest excess, 

 in plates a b, being 0. 70 .21. 



Plate e deviates widely, with a difference in case of a e of 2.03 24, 

 the difference being more than eight times the probable error. The great 

 difference in plate e must indicate variability of the fungus on this plate 

 (cf.with page 152), modification due to influence of some unknown factor of 

 environment, or error in sampling. But since such a variation did occur 

 in a series of plates made with the greatest care and with the same organ- 

 ism, it is clear that the occurrence of such a difference can not properly be 

 interpreted as meaning specific difference. Data from the combined rec- 

 ords of a, b, c, d, and e' (omitting e as questionable) give the most reliable 

 data I have on length of conidia of H. No. 1 under standard conditions 

 (cf. with Graph 42, Fig. K). 



To determine how wide a variability occurs in specimens collected in the 

 open, on the natural host, H. ravenelii (PI. XX) a well-marked, easily recog- 

 nized species of wide geographic distribution, growing on Sporobolus, was stud- 

 ied in conidial-length graphs made from specimens listed in connection with 

 the graphs (Fig. L) . The tabulated results of this study of H. ravenelii follow : 



Nos* 

 4346 

 4347 

 4349 

 4348 

 4350 

 4351 

 4352 

 4353 

 44-^8 

 4449 

 4450 

 4451 

 4452 

 4453 

 4550 

 4551 

 4552 

 4553 



Differences between means 



Nos.* Differences between means 



0.48 

 0.59 

 0.62 

 0.62 

 0.98 

 1.18 

 1.94 

 2.92 

 0.45 

 0.46 

 0.81 

 1.01 

 1.77 

 2.75 

 0.80 

 1.00 

 1.76 

 2.74 



.26 



.24 

 .28 

 .29 

 .27 

 .27 

 .27 

 .26 

 .31 

 .31 

 .30 

 .30 

 .30 

 .29 

 .24 

 .25 

 .25 

 .24 



4650 

 4651 

 4652 

 4653 

 4751 

 4752 

 4753 

 4851 

 4852 

 4853 

 4951 

 4952 

 4953 

 5052 

 5152 

 5153 

 5253 



0.50 

 0.70 

 1.46 

 2.43 

 0.59 

 1.35 

 2.33 

 0.56 

 1.32 

 2.30 

 0.55 

 1.31 

 2.29 

 0.96 



.28 

 .28 

 .28 

 .27 

 .26 

 .26 

 .25 

 .30 

 .30 

 .29 

 .29 

 .29 

 .29 

 .29 



0.76 =t .29 

 1.73 .28 

 0.97 .28 



*For significance of numbers, see Figure L. 



