BEAUTIFUL FERNS. I55 
thickened stalk-bases of next year’s fronds, and the stalks for 
the present year rising a few inches back of the apex. 
The fronds are truly dimorphous, the fertile ones being so 
unlike the sterile, that no one who is unacquainted with the 
plant would suppose they had anything to do with each other. 
The sterile fronds vary in length from one or two inches 
to fifteen or eighteen, and are supported on stalks usually 
rather longer still, so that, while the smallest plants may be 
concealed in the grass, the tallest ones are often fully three 
feet high. The bases of the stalks are flattened, discolored 
and very sparingly chaffy ; the upper part is green in the 
living plant, brownish-stramineous when dried, smooth .and 
naked, rounded at the back, and slightly furrowed in front. 
It contains two obliquely-placed strap-shaped fibro-vascular 
bundles, which unite below the base of the frond and form 
one having a U-shaped section. The outline of the sterile 
fronds is triangular or triangular-ovate. The midrib is winged, 
either from the very base, or from the second pair of segments ; 
the wing at its lower extremity very narrow, but gradually 
widening towards the apex, so that its greatest width is but 
little less than that of the terminal segment. The number 
of segments in the smallest fronds is two or three on each 
side; in the largest fronds twelve or thirteen on each side. 
The lowest segments are rather more than half as long as 
the whole frond ; the next segments usually a little smaller, 
but sometimes a little longer than the first pair, and the 
remaining ones rapidly decreasing. The segments are broadly 
