220 BOTANICAL GAZETTE | SEPTEMBER 
achene itself in length and breadth. In this regard it resembles 
the one or two large tubercled North American species already 
known, but it belongs to a different section of the genus, and its 
other American associates show no such character. It was sug- 
gested that the function of such tubercles (enlarged style bases) 
may be to give buoyancy to the achene in water. 
GrorGE F. Atkinson: Some problems in sporophyll transforma- 
tion among dimorphic ferns—I\n Onoclea sensibilis, the sensitive 
fern, abnormal spore-bearing leaves are sometimes found. This 
form is intermediate in character between the fertile and sterile 
leaves of the normal form of the species, and has been regarded 
at different periods as a distinct species, a variety, or an 
abnormal state caused by the contraction of the vegetative leaf. 
Experimental evidence shows that the form is produced by 
an unfolding and extension of the young sporophyll before its 
characters as such are fully determined, and is caused by a com 
plete or partial loss of the vegetative leaves through injury. 
Cutting off the vegetative leaves in May and again in June 
resulted in a large number of these abnormal forms, together 
with examples of apospory. These results were briefly reported 
at the Brooklyn meeting of the A. A. A. S. in 1894. 
The experiments were continued in 1895 on another species 
of the genus, Onoclea Struthiopteris, with identical results in the 
transformation of the sporophyll, though no cases of apospory 
were observed. During the same year experiments were ah oe 
on Osmunda cinnamomea, but as the fertile leaf has the sporang!@ 
formed in the autumn, and since they appear along a 
sterile leaves in early spring, no results were obtained that 
meenOe. Famine 166 there were a few cases of partial spor” 
ae ll transformation, but the results were not marked since the 
injury to the vegetative leaves was introduced while they — 
very young and long before the incipient development of ess 
sporophyll of the Succeeding year. In 1896 the vegetal’ 
caves were cut in July and again in August, and marked rea 
will be looked for the coming year. 
