BENEDICT: NEW VARIETIES OF NEPHROLEPIS 231 
to more than one hundred different forms in less than fifteen 
years. 
2. Cultural conditions are such as to favor the appearance 
and preservation of variations, because the soil and other en- 
vironmental conditions are probably practically perfect, and 
because very large numbers of plants, one to two million, are 
grown per annum in the United States alone. 
3. The variations may be classified under two headings, pro- 
gressive, and regressive or reversive. Progressive varieties are 
defined as those which show less resemblance to var. bostoniensis 
than their parent forms. Regressive varieties are defined as those 
which show something of a return in characters toward var. 
bostoniensis. 
4. Progressive variations have appeared along three main 
lines, viz., those showing increased division of the leaf; those 
showing increased ruffling of the pinnae; those showing dwarfing. 
Variations showing dichotomy of the pinnae and leaf tips also 
occur. 
5. Progressive increase in division has gone through five vegeta- 
tive generations, each succeeding step being an intensification of 
the preceding, the forms varying from once to five times pinnate. 
Progressive increase in ruffling has gone through three vegeta- 
tive generations. Progressive dwarfing has gone through three 
vegetative generations. 
6. The dwarfing seems to be clearly of two sorts: first, hee 
otic or unilinear; and second, normal in all dimensions. More 
than one type of division sport is also indicated. 
7. Progressive increase in leaf division and progressive dwarfing 
may be expected in any form which has not reached the limits of 
Variation along these lines. 
8. Regressive variations rarely if ever show complete return to 
their parent forms or to var. bostoniensis. 
9. The indicated coefficient of variation for progressive varia- 
tions is very low; probably between one in one million and one in 
one thousand. Regressive variation is much more common. 
10. The variations are all discrete or discontinuous, not pro- 
ceeding by imperceptible differences. 
11. The progressive variations in their differences actually 
