SUCCESSIONS OF THE SAT TAL VALLEY. 255 



Ulmaceae Verbenaceae 



Celtis australis L. Caryopteris WallichiaDa Sohau. 



Urticaceae Vit&ceae 



Boehmeria raaorophylla Don. Vit is lanata Roxb. 



Debregeasia hypoleuca Wedd. ,, lanata glabra. 



Gerardinia beterophylla .Dene ,, semicordata Wall. 



Laportea crenulata Gaud. ,, lanceolaria Wall. 



Summary. 



1. In the region between 4,000 and 5,000 ft. in altitude in the 

 part of Kumaon studied there are three forest types, the'monsoon, 

 dominatod by Bauhinia variegata, B. rettisa and B. VaJilii, the Finns 

 longifolia, and the Quercus incana. This altitude is the upper limit 

 of the Bauhinia and the lower of the pine and oak formations. 



2. The Bauhinia is a distinctively monsoon type almost leafless 

 at the beginning of the rains. It is adapted to great extremes of 

 humidity. 



3. The pine forest has sparse foliage and occupies well drained 

 slopes, crests and ridges. It is adapted to relatively low humidity 

 and high insolation. 



4. The oak forest is of the broad-leaved sclerophyllous type of 

 Schimper. It is adapted to places with no very great extremes of 

 temperature or humidity. 



5. The pine and the Bauhinia are, at this altitude, pioneer forms 

 which tend to be ultimately succeeded by the oak. At a lower 

 altitude the Bauhinia is the climax type. 



6. Xerophytic and hydrophytic successions include numerous 

 pioneer grassy or shrubby stages but the whole tendency is toward 

 the oak. 



7. The influence of man is constantly causing a retrogression of 

 the plant population toward the xerophytic, the climax forest being 

 reapproached by a secondary succession. 



8. The valley abounds in lianas, epiphytes, strangling forms and 

 parasites. 



Grateful acknowledgment is due to Dr. Winfield Dudgeon for 

 loaning a number of the photographs used as well as for giving valu- 

 able hints in this study. 



