The Southern Element in the British Flora. 5^3 



^■^- 



few southern species which are confined to the western part of Great 

 Britain, Meconopsis camhrica, Arahis stricta^ Heliaiithemum gut- 

 tatiim and Trichomanes radicans^ of which the last but one is 

 the only Mediterranean element. If we turn, howeverj to the remainder 

 of the more limited *) species of the southern stock (excepting those which 

 are confined to Ireland) we find the Mediterranean element dominant 

 there being 33 of it against 18 of the Atlantic type. They range as follows: 



Confined in Great Britain to 



West 



Extending 

 to Ireland 



3 (Atl. 2, Med, \) 



2 (Atl. 1, Med. \) 



West and south 13 (Atl. 5, Med. 8) 9 (Atl 3, Med. 6) 



South 25 (Atl. 9, Med. 16) | 3 (Atl. 9, Med. 1) 



South and east (mostly to Norfolk) 3 (all med.) 



West, south and east (to Norfolk) 10 (Atl. 4, Med. 6) I 2 (Atl. 1, Med. 1) 



Pembroke in the west and Norfolk in the east mark off a zone which 



IS particularly rich in Mediterranean forms, the maximum of them occuring 



in the Cornish peninsula. It is characteristic that of the 25 southern 



species confined to the south of England only 3 reach Ireland, and two of 



those are Atlantic, namely Euphorbia hiberna and Simethis plaiii- 

 folia. 



The southern species which are generally diffused through Ireland and, 

 at the same time, Great Britain have already been enumerated. To them 

 have to be added Cotyledon Umbilicus and Lastraea aeioi^la as general 

 in Ireland, but more restricted in Great Britain. The majority of them 

 I'j are Atlantic. So are also, with a single exception, the following ten 

 species, each of which is recorded from 16 to 30 of Praeger's divisions: 

 ^^pidiumhcterophyllum^ Hype^'icum elodes^ Erodium moscha- 

 tum^ TJlex Gallii^ Sedum angliciim^ Rubia peregrina^ Scutel- 

 laria minor ^ Orobanche Hederae^ Iris foetidissima^ Ilymeno- 

 phyllum tunbridgense. 



Among the species with more restricted distribution in Ireland the 

 Mediterranean element gains in number, but it nowhere outnumbers the 

 Atlantic, as it does in the southern counties of England, the nearest ap- 

 proach to equalisation being in Cork West. The Atlantic share of the 

 southern element predominates therefore over the Mediterranean throughout 

 reland. The main area of the southern portion of the Irish flora with 



8-— 29 species per division is in the south, then in the west as far as 

 Gal 



way, and in the east as far as Dublin. In the extreme southwest 

 [l^^rry and Cork West) the Atlantic forms number 18 to 21 species per 



^) Recorded in the >L6ndon CataloffUC< from \ — 25 vice-counties. I count 

 ^^ species as belonging to this class. 



O 



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