FERNS AND FERN AERIES. 169 
2 ; Dryopteris, 11 ; Pkegopteris, 3 ; Woodwardia, 2 ; Camp- 
tosorus, 1 ; Asplenium, 9 ; Adriantum, 1 ; Pteris, 1 ; Pel- 
laea, 2; Poiypodium, 1. The number for this locality, cen¬ 
tral southern New Hampshire, is, so far as at present known, 
12 genera and 25 species. The missing genus is Pellsea, 
an inhabitant almost exclusively of limestone rocks and 
therefore scarcely to be expected here. On the other hand, 
several species not yet reported ar£ to be looked for with 
confidence in our area. Of these more by and.by. 
The figures of Ophioglossum and Botrychium given in 
previous articles have shown how 
in the adder-tongue family, the 
plant throws up a single leaf which 
in fertile plants is divided into two 
portions, a sterile, leaf-like portion 
and a fertile, spike-like portion. 
In the familiar royal fern family, 
the leaves are numerous and, large 
and the plants have quite the as¬ 
pect of modern ferns. Certain 
leaves, or parts of leaves, are de¬ 
voted to the fructification, the spo¬ 
rangia arising from divisions of the 
Fig. 3. leaf which are destitute of chloro¬ 
phyll. In the royal fern the upper part of the leaf, in Clay¬ 
ton’s fern the middle part, and in the cinnamon fern the 
whole leaf, are thus utilized in the process of reproduction. 
The fern family proper (Polypodiaceae), while exceed¬ 
ingly various in the size of the plants and in the size, shape, 
cutting and texture of the leaf, without exception produces 
the fructification on the lower side or margin of the leaves 
or their segments, the sporangia being arranged in clusters 
or heaps (sori). The systematic arrangement of the genera 
depends largely upon the shape and arrangement of these 
sori. Other distinguishing characters are the presence or 
