416 BOTANICAL GAZETTE [DECEMBER 
incised more than a third of the way to the midrib. — A. aculeatum 
Swtz., in several varieties endowed with names, but freely merging, 
varies from a form but little deeper cleft than the most incised form 
of A. munitum to one in which these teeth become pinnae which in 
turn are cleft to the midrib into toothed divisions; that is, it varies 
as from pinnate to tripinnate, the most 
; divided part of fertile fronds being 
io Soe considered in every case. This 
er variation could be duplicated in 
a many ferns. It is doubtless continu- 
ous; but many of our fern species 
sf are founded on differences so small 
that a series of them would not 
bridge the gap between the extremes 
f of this variation. 
- Fig. 8 is a fragment of a very 
ron Aidan maim: es abnormal frond of A. arguum 
Kaulf. Such freaks are not 
exceedingly rare. Some pinnae are usually normally developed, and 
there are all stages between these and mere lumps marking the place 
where pinnae should 
be. These freaks are 
almost always sterile, ‘ Ay fi 
as other very abnor- 27% =e 3 
mal ferns are likely or" 
to be. Reproduction Youd ARS 
is the consummation 
of normal develop- s 
‘ x | 
ment, and any devia- , 
tion from the usual 
course is likely not to 
lead tothisend. Of 
course, this is not true 
of ferns alone. I have found sterile freaks of a number of | owe 
plants among fertile normal forms. Reproduction 4 
decidedly more perfect concatenation of favorable external 
internal conditions than does growth. 
1) 
Fic. 8.—-Aspidium argutum: part of abnormal 
frond, 
