4. CRUCIFER^. 163 



but this would be more of a straining after exactness in 

 physical space, than after essentialities in climate and geo- 

 gi'aphy. The estuary of the Forth is the broad line of 

 sepai'ation between Lowland and Highland provinces ; and 

 its isles have a Lowland climate. 



i/'^f. /// l. JcC/"^ 1 1 9. SiNAPIS INCANA, Lv 



mn. 



Samian. Isles of Jersey and Aldemey. " We learn 

 from the Linnean Herbarium that the S. incana, Linn., is 

 not oiu" ])lant, but only a variety of Brassica nigra, 

 Koch." — Bab. Prim. Flora SarniccE. 



120. SlNAPlS TENUIFOLIA, Br. 



ITrf. III. ^j.ej^ 1 2 3 4 5 6 7 * 9 10 11 12 * 14 15. 



I*-'' ■ South Umit in Devon, Hants, Kent, ^c^^h-e^t^ 



North limit in Fife and Cumberland. 



Estimate of provinces 14. Estimate of coimties 30. 



Latitude 50 — 57. English type of distribution. 



Agi-arian region. Liferagrarian — Midagi'aiian zones. 



Descends to the coast level, in the Peninsula. 



Ascends to 50 or 100 yards, in England. 



Range of mean annual temjDeratm'e 52 — 48. 



Denizen. Viatical and Rupestral. By road-sides, and 

 especially on old buildings. May be native in the south 

 of England ; but in its Scottish localities, it barely claims 

 to be accounted a denizen. There is stUl much uncer- 

 tainty about the pubhshed localities for this species and S. 

 muralis ; the one havuig been frequently mistaken for the 

 other. 



