36 81. NAIAD ACE.55. 



1135. ZosTERA MARINA, Linn. 



1135, b. ZoSTERA ANGUSTIFOLIA, Roth. 



Area 1 2 3 4 * 6 7 * 9 10 11 * 13 14 15 16 17 18. 



South limit in Cornwall, Isle of Wight, Kent. 



North limit in Shetland, Orkney, Hebrides. 



Estimate of provinces 17. Estimate of counties 50. 



Latitude 50 — 61. British type of distribution. 



Agrarian region. Inferagrarian — Superagrarian zones. 



Descends to the sea level, in the Peninsula, 



Ascends, at the sea level, to the North Isles. 



Eange of mean annual temperature 52 — 45. 



Native. Littoral. Eecords for this plant are wanting 

 in three of the provinces ; namely, those of Severn, Trent, 

 Lakes. The Hmited coast-line of the first may render it 

 a real exception to the provincial generality of the species; 

 but the Zostera may still be expected to occur on the 

 very imperfectly examined shores of the two other pro- 

 vinces. The actual number of counties, at present on 

 record for Zostera marina or angustifolia, scarcely amounts 

 to 40. In referring this very littoral plant to the super- 

 agrarian zone, it will of course be understood to imply 

 northern latitude, not elevation above the sea. 



1137*. Naias flexilis, Rostk. 



Hibernian. Recently discovered in Ireland, by Mr, 

 Daniel Oliver, who found it near Roundstone, Cunnemara, 

 Galway, Likely enough to be found in England. 



