chium obliquum_]

New England to Virginia, westward to Minnesota and southward.

_Botrychium obliquum_, var. _dissectum_. Similar to the type, but with
the divisions very finely dissected or incisely many-toothed, the most
beautiful of all the grape ferns. There is considerable variety in the
cutting of the fronds. Maine to Florida and westward.

_Botrychium obliquum_, var. _oneidense_. Ultimate segments oblong, rounded
at the apex, crenulate-serrate, less divided than any of the others and,
perhaps, less common. Vermont to Central New York.

_Botrychium obliquum_, var. _elongatum_. Divisions lanceolate, elongated,
acute.

[Illustration: _Botrychium obliquum_ var. _oneidense_]

Note: A Botrychium not uncommon in Georgia and Alabama, named by Swartz
B. lunarioides, deserves careful study. It is known as the "Southern
Botrychium."

[Illustration: _Botrychium obliquum, var. dissectum_]

(6) TERNATE GRAPE FERN

_Botrychium ternatum_, var. _intermedium_

_Botrychium obliquum_, var. _intermedium_

Leaf more divided than in _obliquum_ and the numerous segments not so
long and pointed, but large, fleshy, ovate or obovate (including var.
_australe_), crenulate, and more or less toothed.

Sandy soil, pastures and open woods. More northerly in its range--New
England and New York. Var. _rutaefolium_. More slender, rarely over six or
seven inches high; sterile segment about two inches broad, its divisions
few, broadly ovate, the lowest sublunate. The first variety passes
insensibly into the second.

[Illustration: Ternate Grape Fern _Botrychium ternatum_ var. _intermedium_
(Reduced)]

[Illustration: Ternate Grape Fern _Botrychium ternatum_ var. _intermedium_
(Two stocks, reduced)]

(7) RATTLESNAKE FERN. _Botrychium virginianum_

Fronds six inches to two feet high. Sterile segment sessile above the
middle of the plant, broadly triangular, thin, membranaceous, ternate.
Pinnules lanceolate, deeply pinnatifid; ultimate segments oblong or
lanceolate and scarcely or not at all spatulate. Fertile part long-stalked,
two to three pinnate, its ultimate segments narrow and thick, nearly
opaque in dried specimens. Mature sporangia varying from dark yellow-brown
to almost black. Open sporangia close again and are flattened or of a
lenticular form. In rich, deciduous woods, rather common and widely
distributed.

[Illustration: Rattlesnake Fern. _Botrychium virginianum_ (From Waters's
"Ferns," Henry Holt & Co.)]

Prince Edw