TRANSFORMATION OF SPOROPHYLLARY. 175 



vided with chlorophyll, but thus far no antheridia or arche- 

 gonia have been found. These prothalloid growths resemble 

 very much some of those which are developed from the placen- 

 tal region of Pteris aquilina L., and first described by Doctor 

 Farlow in the Annals of Botany, II, 1888, p. 383. The same 

 condition of Pteris aquilina was noted by myself in the autumn 

 of 1893, at Ithaca, N. Y. 



When the experiment with Onoclea sensibilis was undertaken, 

 no serious thought was given to an attempt to produce like 

 conditions by artificial treatment with the other species of this 

 genus, namely, Onoclea struthiopteris. However, on July 14, 

 after observing the result which was attending the experiment 

 with Onoclea sensibilis, I determined to try the Onoclea struthi- 

 opteris even at this late date. The fern is very abundant on 

 an island in Fall Creek, where vegetation is very rank and the 

 leaves of the ostrich fern attain a height of 150 cm. or more. 

 The leaves from fifty or sixty stools of this fern were cut 

 away, the leaves then having attained their maximum height 

 for this locality. In this number of stools there were half a 

 dozen in which there were fertile leaves already 15-25 cm. in 

 height. 



The experiment was inspected on August 10. The fertile 

 leaves which were up on the I4th of July had matured their 

 sporangia and were, to all appearance, normal. There were 

 many rudimentary fertile leaves only partly unrolled, three to 

 six inches in height. These were also found among the stools 

 of the fern which had not been disturbed. For a long time 

 during the spring, the ground here was under water, and this 

 may have had some influence in aborting many of these leaves. 

 That many of them were of the fertile kind was manifest by the 

 peculiar revolute character of the rudimentary pinnules. 



Very few of the stools from which the leaves had been cut 

 on the 1 4th of July had put forth new leaves. Ten or twelve 

 had produced one to four leaves, ranging from one to two feet 

 high. Very careful search was made to discover some sign of 

 a sporophyll partially transformed, and I was about to conclude 

 that the experiment was a failure for that year because entered 

 upon at so late a date. At last a single leaf was found in a 



