DISTRIBUTION AND AFFINITIES. 21 
21. Connaught (W.). Leitrim, Sligo, Galway, Ros- 
common. 
22. Leinster (E.). Longford,Westmeath,Meath, Louth, 
Dublin, Kildare, King's, Queen's, Wicklow, Wex- 
ford, Carlow, Kilkenny. 
23. Munster (S.) Waterford,Tipperary, Clare, Limerick, 
Cork, Kerry. 
24. Channel Isles. Guernsey, Jersey. 
The proportion which the ferns bear to the phsenoga- 
mous portion of the flora of the British Isles, may be 
taken in round numbers, as 1 to 35. In Scotland, they 
are computed to hold the proportion of 1 in 31. The 
geographical distribution of ferns, generally considered, 
shows an enormous disproportion between them and the 
rest of the flora in certain tropical islands : thus, in Ja- 
maica, they are l-9th of the phsenogamous plants ; in 
New Guinea, they bear the proportion of 28 to 122 ; in 
New Ireland, they are as 13 to 60 ; and in the Sandwich 
Isles, as 40 to 160. It is clear from the collections of 
Wallich, that ferns must form an important feature in the 
vegetation of the Indian Archipelago. Upon continents, 
however, they are found to be far less numerous : thus, 
for example, in equinoxial America, Humboldt does not 
estimate them higher than 1-3 6th ; and in New Holland, 
Brown finds them l-37th. They decrease in proportion 
towards each pole; so that in France, they stand as 
l-63rd ; in Portugal, as l-116th; in the Greek Archipe- 
lago, as l-227th ; and in Egypt, as l-971st of the flower- 
ing plants. Northwards of these countries, their propor- 
tion again augments, and they are found to form l-31st 
of the phsunogamous vegetation of Scotland, l-35th in 
Sweden, l-18th in Iceland, l-10th in Greenland, and 
l-7th at North Cape. The Adder's tongues (Ophioglot- 
saceaR) are most abundant in the islands of tropical Asia ; 
they occur, however, in the West Indies, and are not un- 
common in the temperate latitudes of both hemispheres. 
