THE COMMON POLYPODY 
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general form somewhat narrowly egg-shaped, tapering to a 
point, more or less blunt at its apex, broadest about the 
centre, and slightly narrowing towards the base. It is what 
is called pinnatifid, the leafy expansion on each side of the 
racliis — which, like the stipes, is smooth and of a whitish 
green — being cleft down almost close to it, having on both 
sides a row of blunt-pointed lobes about an inch long, and 
rather more than a quarter of an inch broad, fastened to the 
mid-stem or racliis in alternation, and by the whole width of 
their bases. Through each lobe runs a tortuous and some- 
what rigid and prominent mid-vein, from both sides of which 
radiate three or four times branched venules, most of them 
terminating in little club-shaped heads close to the margins 
of the segments or lobes. Some of these club-headed 
venules, however — and one at least on each of the forked 
series — terminate midway between the mid- vein and the lobe 
margin, and upon these shorter venules in the fruitful lobes 
are borne the sori. There is thus a double row of the sori 
on each lobe, one on each side of the mid-vein. The sori 
are round, light straw-coloured when young, then yellow, 
and finally orange-coloured. They are mostly confined to 
the upper half of the under side of the frond, and when ripe 
and ranged, as they often are, in closely-set lines, they give 
to the frond an extremely beautiful appearance. There are 
about forty varieties in the British Islands of the normal 
form of Poly podium vulgare. 
Distribution. — Like most of the British species of Ferns, 
Polypodium vulgare is distributed pretty widely through 
European countries, being an inhabitant of Corfu, France, 
Germany, Italy, Sardinia, Scandinavia, Sicily, Spain, and 
Switzerland. In Asia, it occurs in Armenia and Kamt- 
schatka. I11 Africa, in Algiers, the Canary Islands, and 
Madeira. It is found in the United States of America, in 
Canada, Guatemala, and Mexico. In the British Islands 
