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AMERICAN JOURNAL OF BOTANY 
[Vol. 9. 
continued constant, and show no indication of fluctuating variations toward 
a more divided form.'' A second instance of this reversion has also taken 
place at the Brooklyn Botanic Garden in material of superhissima obtained 
originally from the city greenhouses of Fairmount Park, Philadelphia. 
So far it has not been sufHciently grown to allow an opinion as to its identity 
with Pierson's viridissima. 
From viridissima, although no fluctuating variation has been observed, 
there has developed in at least two establishments a further reversion of 
stable character, in this case one of size. This new form (PI. VIII, fig. 4), 
which has not received any name, is taller and laxer, thus intermediate in 
size and habit between viridissima and normal hostoniensis. It has not, 
however, made complete return to hostoniensis size but is comparable to 
the ''New York'' fern, described on a preceding page as a reversion from 
Giatrasi. Like that form, it is stable in its characters, and it may here be 
noted as a general observation that the mutations showing reduced size 
are invariably more stable than those presenting differences in amount of 
leaf division. This semi-dwarf mutation from viridissima was first noted 
by Trevillian in the Pierson establishment. Since then I have found it 
also in the greenhouses of Peter Wagner of Brooklyn. 
From superhissima there has developed directly another reversion in 
size (PI. VIII, fig. 7), but which has retained the double division of both 
superhissima and Piersoni. This also was first noted in the Pierson green- 
houses where it has developed in superhissima stock more than once. It 
has also occurred in the greenhouses of John Lewis Childs at Floral Park, 
and likewise at the Brooklyn Botanic Garden. A description of the cir- 
cumstances of this last occurrence is worth recording. 
In a pot of superhissima which included three or four crowns, there 
developed in one crown two leaves considerably taller and looser in division. 
The crowns were then potted separately for observation. That containing 
the two taller leaves developed more of the same sort of leaves, becoming 
eventually intermediate in size between superhissima and Piersoni. Ad- 
ditional plants were raised from it of the same sort, and the form remained 
stable in further cultivation. 
It should be noted here that the several reversions of this particular type 
have not resulted in exactly identical forms. The different plants are all 
intermediate between superhissima and Piersoni but there are some varia- 
tions in height and shape of the segments. 
Special interest attaches to the three reversionary forms above described 
because of their very definite character. Each represents a single return 
toward the original Boston-fern type. In all three cases the new forms were 
^ Since the above sentence relating to viridissima was written, a further variation has 
taken place in this form, first noted in the summer of 192 1 . In the only plant of viridissima 
being maintained, what appears to be a definite return to the characteristics of superhissima 
has occurred, so that there is now no authentic plant of the original Pierson viridissima 
sport in the Botanic Garden collection. 
