68 



THE FERX BULLETIN 



formed first and therefore should lose their plasticity 

 long before the tip does so. As a matter of fact, this 

 is shown in practically all these curious changes, for 

 when a fertile frond becomes partly sterile, it is the 

 newer tip that makes the change. If any part is fer- 

 tile it is likely to be the lower parts as shown in our 

 illustration. It is well known that fern fronds are 

 completed, so far as the making of additional cells is 

 concerned, for some time before they appear above the 

 earth, their subsequent development being largely an 

 increase in the size rather than in the number of the 

 cells, so that when the frond is fully formed it is doubt- 

 less incapable of change though it may not be destined 

 to be unfurled for months to come. In many ferns the 

 sporangia are developed from single cells on the sur- 

 face of the frond and it may be possible that in such 

 species the power to produce spores exists even after 

 the frond is formed, but nothing very definite seems to 

 be known on this point. 



FERNS OF BLOOMINGTON, INDIANA. 



By F. C. Greene. 

 Bloomington. the seat of Indiana University, is situ- 

 ated in the great Mississippian limestone belt of south- 

 ern Indiana. However, the Knobstone, with its deep, 

 shaded ravines and dry points, is found less than a mile 

 to the east, while large cliffs of sandstone occur a few 

 miles to the west. Each locality adds variety to the 

 fern flora, although many species are common to all 

 three. 



A short walk in any direction will be almost sure to 

 disclose Cystopteris fragilis, Phegopteris hexagonop- 

 tera, Adiantum pedatum, Polystichum acrostichoides 

 and Botrychum Virginianum. The deep Knobstone 

 ravines contain luxurious plants of Asplcnium angusti- 



