220 BENEDICT: NEW VARIETIES OF NEPHROLEPIS 
form in one or more further vegetative generations. In these three 
lines occur all the illustrations of progressive orthogenetic varia- 
tion about which this paper is mainly concerned. Reversion or 
regressive variation is also common, but need not be considered 
here. 
The variations classified as progressive according to the diss 
tinction already made are all arranged according to their origin 
in the chart on page 219. It should be understood that no attempt 
has been made at this time to include the English forms, as they 
are not yet available for study, but enough is known to indicate 
that they do not represent any kind of variation not shown by 
American forms. 
The direct sports from var. bostoniensis are of further interest 
in connection with the present discussion only as they have given 
rise to progressive variations. Upon this basis we may eliminate 
at once the varieties, Schillert, Anna Foster, Schultheisi, and 
Wittboldi. It does not follow that these varieties have no poten- 
tialities of variation. Their failure to vary has probably been 
due only to the fact that they have never been extensively culti- 
vated, and this in turn, has been due to the fact that they have 
not offered to the florist sufficient inducement in the way of 
horticultural possibilities. It remains then to consider the othe 
bostoniensis sports according to the lines of progressive variation 
which they exhibit. 
3. Progressive division of the leaf 
(PLATES 10-12) 
Of the original bostoniensis varieties showing an increase 1? 
leaf division, Piersoni is of most importance. From this form 
have come three or possibly four types of sports, viz., varieties 
showing further increase in division, Barrowsi, elegantissvmd, 
and elegantissima-compacta: varieties showing dwarfing, super- 
abet a variety with forked pinnae, splendida; and a so-called 
“improved” form, Piersoni “ improved.” 
Piersoni represents a twice-pinnate sport from the once-pinnate 
var. bostoniensis. Barrowsi shows a slight increase in the lobing 
of the pinnulae, that is, it is twice-pinnate pinnatifid. Elegan- 
