34 AMERICAN FERN JOURNAL 
The reviewer is especially interested in this group 
of ferns, and has been making it the object of special 
study for ten years intermittently. As a result of this 
study he is obliged to dissent emphatically from some of 
the conclusions indicated above. The statement that 
dilatata grades into spinulosa is, the writer believes, en- 
tirely incorrect. The spinulosa group is and has been 
correctly divided into its three constituent forms, 
spinulosa, intermedia, and dilatata, by general usage in 
this country. All three forms are well distinguished, 
specifically, the writer believes. 
In its typical development, the distinguishing features 
of Fernald’s var. americana as distinguished from typical 
European dilatata are found only in its concolorous scales 
as opposed to dark striped ones, and its glandless indusia 
as opposed to glandular indusia. Now there can be no 
doubt that dilatata of eastern North America differs 
in these particulars from typical dilatata of Europe, 
and may well deserve to be separated as a variety of 
dilatata? but that these characters constitute sufficient 
difference to separate it from dilatata entirely and attach 
it to spinulosa seems far from established. 
There is scarcely space here for an extended discussion 
at this time, particularly as the writer hopes to indulge 
in an extended one in connection with a paper on the 
spinulosa group some time this year. It may be of 
interest, however, to record some observations made at 
the Gray Herbarium on the material Prof. Fernald had 
studied and identified. 
1. Americana is not limited to America but occurs 10 
Eurasia. That is, in the reviewer’s opinion, dilatata 1s 
represented in eastern North America almost entirely 
by the form with pale scales and glandless indusia, but 
this same form of dilatata also occurs sparingly through- 
out its whole range. The leaf form is always the same- 
? So separated, it should be called Dryopteris dilatata var. american® — 
“ ope 
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