Rootstock short, its base including the buds of succeeding years. Fronds
two to twelve inches or more high. Leafy or sterile segment triangular,
ternate, long-petioled, springing from near the base of the plant, and
spreading horizontally. From the main leafstock grow several pairs of
stalked pinnæ, with the divisions ovate-oblong, acutish, crenate-serrulate,
obliquely cordate or subcordate. Fertile segment taller, erect, about three
times pinnate, maturing its fruit in autumn. Occasionally two or three
fertile spikes grow on the same plant. In vernation the apex of each
segment is bent down with a slight curve inward.
[Illustration: Common Grape Fern. _Botrychium 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 oblìquum_, var. _oneidénse_. 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 oblìquum_, var. _elongàtum_. 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
_Botrýchium ternàtum_, var. _intermèdium_
_Botrýchium oblìquum_, var. _intermèdium_
Leaf more divided than in _oblìquum_ and the numerous segments not so
long and pointed, but large, fleshy, ovate or obovate (including var.
_austràle_), crenulate, and more or less toothed.
Sandy soil, pastures and open woods. More northerly in its range--New
England and New York. Var. _rutaefòlium_. 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 virginiànum_
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 Edward Island, Minnesota, south to Florida and Texas, and north to
Newfoundland and Labrador.
Var. _grácilis_. A form much reduced in size.
Var. LAURENTIÀNUM. A conspicuous variety having thick and heavy sterile
fronds less finely divided than the type, with the segments crowded to
overlapping. Pinnules shorter than the type, tending to be ovate, outer
segments strongly spatulate. Fertile spike relatively short and stout,
strongly paniculate when well developed. Ultimate segments flat, folaceous,
one mm. wide. Mostly confined to the limestone district near the Gulf of
St. Lawrence, Labrador, Newfoundland, Quebec, Maine, and Michigan.
Var. INTERMEDIUM. Segments of sterile fronds ultimately much spatulate,
previously ovate, not overlapping. Segments of fertile fronds ultimately
narrowly flattened. (For this and the other varieties see Rhodora of
September, 1919.) Nova Scotia, Maine, Vermont, Massachusetts, Connecticut,
northern New York, Illinois, and Missouri.
Var. EUROPÀEUM. Fertile frond less finely dissected than in type. Ultimate
segments more obtuse than in type; has but very slight tendency towards the
spatulate form of the two previous varieties. Pinnules lanceolate, strongly
decurrent so that the pinnæ are merely pinnatifid. In coniferous forests
of Canada, and confined to calcareous regions. Quebec, New Brunswick, New
Hampshire, Vermont, New York, Ontario, Montana, and British Columbia. Said
to be rare even in Europe.
V