8 
III. Polypods. Folypodiacecd, Clusters on the back 
of the frond* with or without a cover. Bags of spores with 
a jointed elastic ring. Buds rolled in. 
We will next proceed to consider the genus and species 
of each Sub-order. If we meet with a plant having a leaf and 
a spike undivided, and growing in wet clay or loamy fields, 
it is most probably an Adder’ s-tongue, Ophioglossum^ but 
if we meet with one having a pinnatifid leaf and a clustered 
spike on a dry sandy or peaty soil, we should inspect it and 
see whether it be the Moonwort, 'Botrychium. Thus we 
determine the genera of the first Sub-order. 
I. TONGrlJEWOE/TS. OpTiioglossacece. 
1. Adder’s-tongues. OpJiiogloss^i^ Clusters of fruit on 
a two-rowed spike attached to an undivided frond. 
2. Clustered Tongue worts. Botrychidfi^ Pructification 
on a clustered spike with a deeply divided frond. 
If we observe a Pern-like plant with the rust-red fruit 
growing at the ends of the fronds, and not on the back of the 
leafiets, and without an elastic ring to. the bags of spores, we 
may take it for granted that this is an Osmunda, the only 
British genus of the Second Sub-order. Hence we proceed. 
II. OSMUNDS. Osmundacece, 
Osmunda. Pruit growing on a clustered branch at the 
end of a frond. Bags of spores without an elastic ring. 
We now come to the Third Sub-order, which takes in all 
the other British, and by far the greater part of the Perns 
found in the whole world, from the Tropics to the Arctic 
and Antarctic regions. They vary exceedingly from the 
largest tree ferns to the smallest species scarcely perceptible 
to the eye. To facilitate the discovery of these plants, our 
British Polypods are divided into four families. In most 
species the clusters of fruit have a thin white or very light 
* Some genera have the clusters on a columnar receptacle arising from their side 
veins. These not found here. 
