F E R N S OF NORTH AM E R IC A .
Brit. W. I. Islands, p. 666.— H o o k e r & B a k e r , Syn. Fil., p.
46.— F o u r n i e r , PI. Mex., Crypt., p. 12 7.— K e y s e r l in g , Gen.
Adiantum, in Mem. Acad, de St. Petersb. ser, vii., xxii., No.
2, p- 13. 3 5 -— E a to n , in Bulletin of Torr. Botan. Club., vi.,
p. 30 6 .
H ab.— Banks of Halifax River, Florida, Mr. S, N. C hamberlin,
Miss M. C. R eynolds, May, 1877. Sides of ‘ sinks’ in limestone near
Ocala, Florida, Mr. W. H . S hockley and Mr. C hristian Beh (March,
1878), and gathered abundantly near the same place, by Capt, J. D onnell
S mith, in April, 1879. A common fern in the West Indies, Bermuda,
Mexico, Venezuela and some parts of South America. Plants
from Florida referred to this species by Dr. Chapman are A . Capillus-
Veneris, and the name was given by Dr. Torrey in Emory’s notes of a
Military Reconnoisance, p. 155, to specimens of A . Capillus-Veneris
and A . cmarginaiuni.
D e s c r i p t i o n ; — The root-stock is creeping, and about as
thick as a goose-quill, but owing to the many short nodose
lateral branches which it often bears, it appears much thicker.
It is covered with fuscous-brown ovate-acuminate ciliated chaff
intermixed with narrow chaffy hairs.
The stalks are often a foot long, and sometimes exceed
this measure by several inches. They are erect, terete, rigid,
smooth, almost if not quite black in color, and have as fine
a polish as is ever seen in ferns. The largest ones are a line
and a half thick near the base. The fibro-vascular bundles
are two at the base of the stalk, but they presently unite
into one showing in its section the form of a V. All the
F E R N S OF NORTH AM E R IC A . 233
branches of the rachis have the same ebony-like color and
polish.
The largest fronds are over a foot long, and nearly as
broad at the base as they arc long; so that the outline is
broadly triangular. The lower primary pinnæ have a stalk
from two to four or five inches long, and the stalks of the
rest of the pinnæ and pinnules are successively shorter, those
of the ultimate pinnules being from one to three lines long.
The second primary pinna is very often rather larger than the
first, but the rest of the pinnæ rapidly diminish and become
simpler, so that the ninth or tenth pinna is reduced to a
single pinnule. All the pinnæ and pinnules are strictly alternate,
and the arrangement of the frond is anadromous throughout,
the first pinnule being always on the upper side of the
rachis of the pinna to which it belongs.
The ultimate pinnules are in general rhomboid, though
many of them, especially the terminal ones, have the outer
and upper margins rounded into one continuous curve. They
vary in length from three or four lines to nearly an inch.
The base is an angle of from about sixty to one hundred and
thirty degrees, but oftenest about a right angle. The outer
and upper margins are lobed, usually slightly, but sometimes
to a depth of two or three lines. In the sterile fronds the
lobes are denticulate, the veinlets extending to the points of
the teeth. In the fertile fronds the ends of the lobes are
recurved to form the fruiting involucres, which are from four
to twelve to a pinnule, short, transversely oblong, or somewhat
crescent-shaped, and often slightly two-lobed.
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