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1915] Book Review 67 
Also in trop. Am." and in New York is known only from * Babylon, 
L. I.” (p. 66), thus disregarding its occurrence on Nantucket (Bick- 
nell, Bull. Torr. Bot. Cl. xxxv. 55), on Staten Island (Clute, Fern 
Bull. ix. 9), and at Southampton, L. I. (Clute, l. c. xiii. 88). 
'These illustrations serve sufficiently to indicate the quality of the 
compilation upon which the generalizations are based, and to suggest 
that, when in the Preface the author referred to “the incompleteness 
of our present knowledge," he was presumably speaking editorially. 
As to the generalizations themselves, they consist largely of an amplifi- 
cation of the author's previously published thesis, that the Pine 
Barren flora of New Jersey occupies an area (the Beacon Hill forma- 
tion), which escaped Pleistocene glaciation, and there persisted 
essentially unchanged through the Pleistocene, while the vegetation 
of surrounding areas was highly modified. Of the validity of the data 
and the conclusions on this point the reviewer is not competent to 
judge; but when the author enters the regions to the northeast of 
New York city and attempts to generalize without regard to the 
geological (and often botanical) evidence, he certainly overworks 
glaciation and lack of glaciation. This tendency has already been 
commented upon, and the following extract, from page 24, is to 
the point. 
“38. In this connection the distribution of the most remarkable plant of 
the pine-barrens, Schizaea pusilla, is very interesting. It is found only in the 
pine-barrens and in Nova Scotia and Newfoundland, and is unknown between 
these points. If Dr. Scharff's recently proposed theory that perhaps parts of 
Nova Scotia and Newfoundland remained unglaciated through all the period 
of the Pleistocene is correct, then it is not impossible that Schizaea is a relict 
in the pine-barrens of its southern migration, and that it is also a relict in the 
north, all the intervening territory having been preempted first by the ice, 
secondarily by more ‘aggressive’ plants after the recession of the ice. This is 
little more than interesting speculation, but Scharff, whether wrong or right in 
his contention, has opened up a wide field of discussion. It is certainly 
significant that Schizaea is not found in the unquestionably glaciated country, 
and is found only in the pine-barrens and in the [probably] unglaciated north- 
east. -An almost similar distribution is that of Aster nemoralis, which is lacking 
in the intervening territory between its northern outposts in northern New 
York and Newfoundland and its southerly stations in New Jersey." 
Now, any conclusions based upon the assumptions above quoted 
are bound to lead diametrically away from the truth. In the first 
place, an author who supposes that Schizaea pusilla made a “southern 
migration" to New Jersey overlooks the fundamental fact that Schizaea 
is not a boreal, but a Tropical and austral genus. Hooker recognized 
26 species and Christensen, though differing slightly in his interpreta- 
tion, maintains the same number. Of these, 9 are confined strictly 
to the Southern Hemisphere (Australia, New Zealand, South Africa, 
