Oct. 1849. AUTUMNAL VEGETATION. 181 



We descended to Yeumtong in a cold drizzle, arriving 

 by sunset ; we remained through the following day, hoping 

 to explore the lower glacier on the opposite side of the 

 valley : which, however, the weather entirely prevented. 

 I have before mentioned (p. 140) that in descending in 

 autumn from the drier and more sunny rearward Sikkim 

 valleys, the vegetation is found to be most backward in the 

 lowest and dampest regions. On this occasion, I found 

 asters, grasses, polygonums, and other plants that were 

 withered, brown, and seeding at Momay (14,000 to 15,000 

 feet), at Yeumtong (12,000 feet) green and unripe ; and 

 2000 feet lower still, at Lachoong, the contrast was even 

 more marked. Thus the short backward spring and 

 summer of the Arctic zone is overtaken by an early and 

 forward seed-time and winter : so far as regards the 

 effects of mean temperature, the warmer station is in 

 autumn more backward than the colder. This is every- 

 where obvious in the prevalent plants of each, and is 

 especially recognisable in the rhododendrons ; as the 

 following table shows :- — ■ 



16,000 to 17,000 feet, R. nivale flowers in July; fruits in September =2 months. 



13,000 „ 14,000 feet, R. anthopogon flowers in June; fruits in Oct. =4 months. 



11,000 „ 12,000 feet, R. campamdatum flowers in May; fruits in Nov. =6 months. 



8,000 „ 9,000 feet, R. argenteum flowers in April; fruits in Dec. =8 months. 



And so it is with many species of Compositce and TJmbelli- 

 ferce, and indeed of all natural orders, some of which I have 

 on the same day gathered in ripe fruit at 13,000 to 14,000 

 feet, and found still in flower at 9000 to 10,000 feet. The 

 brighter skies and more powerful and frequent solar radia- 

 tion at the greater elevations, account for this apparent 

 inversion of the order of nature.* 



* The distribution of the seasons at different elevations in the Himalaya gives 

 rise to some anomalies that have puzzled naturalists. From the middle of 



