236 
on the insects of New Jersey has figured the ‘‘entomological 
pine-barrens" as very nearly coinciding with the floral pine- 
barrens.5 І have not been able to find any explanation of these 
curious distributional features, by a zoólogist; but it would seem 
that perhaps the outline given above may also explain for them 
the endemism of the pine-barrens. 
In the light of this historical outline it should be easy to trace 
the development of the pine-barren vegetation from the Miocene 
uplift until the present. Ancestrally it must have consisted of 
purely American plants, and most of these, in all probability, 
were of southern extraction." Of the 565 species reported grow- 
ing in the region, not counting weeds, 386 are listed as truly 
pine-barren. This does not mean that they are found nowhere 
else, but that so far as New Jersey is concerned these plants find 
their greatest development in the pine-barrens. There is a 
small element among them practically unknown outside of the 
pine-barrens of New Jersey, such as Abama americana, Sporobolus 
Torreyanus, Eupatorium resinosum,? Chrysopsis falcata, and 
Juncus caesariensis.? Besides these there are 12 species found 
predominately in this region, whose distribution is restricted 
from Massachusetts on the north to Delaware on the south, 
and whose undoubted distribution-centers are the pine-barrens. 
It would seem likely that the 386 pine-barren species mentioned 
above which are now found elsewhere on the coastal plain have 
spread there since the release of the Beacon Hill formation from 
its last isolation. Perhaps future studies may be able to show, 
even in the pine-barrens themselves, a greater development of 
the typically endemic pine-barrens in the interior, than is found 
near the edges where the former and existing tension between 
other elements has left greater evidences. 
At the advance of the ice there must have been a great invasion 
of northern species, many of which are still found in the pine- 
16 Ann. Rept. №. Jersey State Mus. 1909. Map нс 1910 
17 Over 180 species of the present flora range from Virginia to Florida nd north- 
ward. Of these more than 70 find their northernmost sei 5 in the pine-barrens. 
The others are found further north, into Massachusetts and Rhode Island. These 
and subsequent figures are from Mr. Stone's excellent tabulations. 
18 Apparently unknown elsewhere in 
