INTRODUCTION. 



the leaves of spring-flowering plants, especially Prunus spinosa, appear to 

 be retarded. (Decreasing influence of the riparian climate with its mild 

 winter.) The sinking of the curve of the blossoming of spring-flowering 

 plants towards the East is indicated on the chart by the dotted isophanal 

 lines on the German Ocean. 



4. The blossommg of summer-floivering plants is, on the contrary, later 

 in the West, earlier in the East towards Giessen. (Warmer continental 

 summer). 



5. In the central mountain-region the blossoming of spring-flowers is 

 retarded (later melting of the snow) ; while with summer-flowering plants 1 

 It is nearly the same — as, e.g., in the Alps as compared with Giessen : — 

 Secale, Solidago virgaurea (strong insolation from the clearness of the air 

 and favourable exposure) ; while the ripening of fruit is usually retarded , 

 in proportion to the absolute altitude. (Earlier commencement of the ' 

 autumn with falling temperature.) 



6. The ripening of fruits is earlier at Prague and Cracow than in 

 ■Giessen, being delayed as you advance westwards (continental summer). 



7. The interval between blossoming and ripening of fruit is well known 

 to be shorter in the far North than in Central Europe. This is true for 

 all those plants for which the increase of warmth from the longer day 

 affords sufficient compensation. Where this is not the case, the fruits do 

 not regularly ripen. (In Giessen the bilberry, Vaccinium Myrtillus, 

 ripens in July ; in Iceland in September. In the " Tundress" of Northern 

 Siberia, the species of Vaccinium do not usually ripen their fruits, 

 -although widely dispersed by birds.) 



8. The same interval is, in the mountain-region of Central Europe, in 

 ihe case of ^scultes, shortest north of the Alps above 500 m., longer in 

 the higher mountains at 600 m. or more. With Secale the length of time 

 »does not increase simply with the height ; a secondary influence, that of 

 "exposure, which changes with the locality, has a powerful effect. 



9. The colouring of the leaves appear to commence earlier in the West 

 ((south of England) than at Giessen. 



10. The ninth fihenological province, so extensive in the far North 

 ^thirty-two to about sixty days after Giessen ; see chart), appears to be 

 -entirely wanting in the South, even in higher Switzerland. By this re- 

 tardation, the ripening of the fruits of spring-flowers ^e.g., Prunus Padus 

 and Ribes rubruni) is rendered possible in the far North by the influence 

 lof the very short but very hot summer (long days), while in higher 

 Switzerland this compensation fails. 



