208 BENEDICT: NEW VARIETIES OF NEPHROLEPIS 
named horticultural forms besides a probably equally large 
number which have never gained horticultural recognition. The 
present account is concerned only with a portion of these Boston 
fern varieties, the basis of selection being indicated below. 
Reproduction in the Boston fern and its varieties, as indeed in 
the varieties of the other species of Nephrolepis, is almost exclu- 
sively vegetative. The varieties with a few possible exceptions 
have arisen strictly by bud variation, the explanation being found 
in the fact that almost all the forms, the wild species being ex- 
cepted, produce imperfect sori with mostly abortive sporangia. As 
indicated, there are a few varieties reputed to have been raised 
from spores and there is nothing impossible in this connection, 
but there is also no question that the great majority of forms 
have developed from bud sports. Their study is therefore un- 
troubled by questions of pure line or hybridization, nor does it 
readily allow these valuable analytical methods of attack, but calls 
mainly for an accurate determination of the origin and parentage 
of each form and an adequate description of its characters. 
The large number of varieties mentioned includes a multi- 
plicity of forms, some of which have arisen by progressive, some 
by regressive, variation. A complete description of all these at 
present would involve considerable difficulties in the way of 
preparation and presentation. The scope of this paper is there- 
fore limited to deal mainly with the more pronounced lines nf 
progressive variation. The terms “progressive,” “regressive, 
and “reversion,” are used here with only their ordinary non- 
technical connotation. Progressive variations as understood 
are those which show less resemblance to var. bostoniensis than 
do their parent forms. It must be understood here that the 
variations from var. bostoniensis include series of forms with as 
many as six successive intensifications of a given character by 
which the first of the series diverged from var. bostoniensts. 
Such a series is considered progressive (see PLATE 10). Regressive 
variations or reversions, on the other hand, are understood to be 
those which show something of a return in characters toward var. 
bostoniensis. This classification is largely one of convenience, 
and the separation of the two types of forms may not always be 
justified as made. It will, however, furnish a good basis for 4 
description and discussion of these forms. 
