March, 1922] BENEDICT — NEW VARIETIES OF NEPHROLEPIS 
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height. There is no indication of ''fixed instability" here. Both Giatrasi 
and the ''New York'' fern are discontinuous and stable sports, without 
fluctuations inter se. 
The case of the New York Nephrolepis emphasizes a fact true in general 
for reversions: complete return to all the characters of the parent form 
rarely if ever occurs. The original progressive variations were not mere 
fluctuating changes about a mean, but decided and permanent changes 
which must find their explanation in some cytological alteration of definite 
character. 
Summarizing, we may note the following types of reversion among the 
primary progressive sports of hostoniensis: 
1. A reduction in the stability of the original progressive change, as 
shown by a permanent decrease in the proportion of divided leaves in Anna 
Foster and probably also in Piersoni. It is possible that this type of rever- 
sion should be considered as a fluctuation. 
2. A possible reversion (mutation) to a fertile condition, with the 
Piersoni-like form from the New York Botanical Garden as an illustration 
(PI. V, figs. 13-17; PI- VI, fig. 6). 
3. A reversion (mutation) from a dwarf form to a size intermediate 
between the dwarf and hostoniensis (PI. VIII). 
N.B. The production of single atypic leaves does not constitute reversion 
but rather merely part of the normal variability of a given plant (PI. V, 
figs. 1-17). 
Reversions of the Secondary Sports of Bostoniensis 
Reversions of superbissima (PI. VIII, fig. 6). 
The simplest examples of reversion among the secondary sports of 
bostoniensis have occurred in plants of the variety superbissima. This is 
a dwarfed sport from Piersoni, and differs from the latter form almost 
entirely in a foreshortening of the rachis and of the midribs of the pinnae. 
The actual amount of green tissue does not seem to be proportionately 
reduced. As a result of this brachytic type of dwarfing, the leaves have a 
crowded and congested appearance. In type of division and stability of 
leaf division, superbissima seems to be exactly like Piersoni. In the course 
of a year any given plant is sure to produce a good many once-divided leaves. 
Two distinct reversions have been noted and are represented by forms which 
have been continuously cultivated. 
The first of these was introduced as a new variety by Pierson under the 
name of viridissima (PI. VIII, fig. 5), given on account of its dark green 
color, presumably the result of the congestion of leaf tissue. This form is 
of the same size as superbissima and has the same rigid thick rachides, but 
is entirely once pinnate like bostoniensis. In other words, it represents a 
reversion in one of the two progressive characters of superbissima, that of 
leaf division. The plants of viridissima, as grown for some years, have 
