446 BOTANICAL GAZETTE [may 



papillae. The leaf area of the sun foliage is approximately the same as that 

 of the shade leaves, but the latter are decidedly larger and narrower. Red 



common 



story 



to have a higher rate of respiration. The percentage of carbon dioxide within 

 the forest is shown to be high, and here light is doubtless the limiting factor 

 of photosynthesis. 



Brown agrees with McLean in recognizing valley and mountain forest 

 types, and in addition describes a distinct transition form. The lowland type 

 of the part of the Philippines under consideration is the Dipterocarp forest 

 and extends to an altitude of 600 m. It exhibits distinct strata or stories 

 composed of vegetation 40, 20, and 10 m. high respectively. Epiphytes are 

 largely phanerogams, and are confined chiefly to the largest branches of 

 the tallest trees. Buttressed trees and cauliflora are developed by many 

 species, while the ground covering is characterized by rattans in the rosette 

 stage. On a typical plot there were 22 first 

 species, and 23 lower story species. 



The midmountain forest extends from 600 m. to an elevation of about 

 goo m. and shows two stories of about 18 and 8 m. in height. One typical 

 association is termed the Quercus- Niolitsea forest from the most abundant 

 genera. The undergrowth is less dense, but the ground cover of ferns and 

 herbaceous plants is better developed than in the Dipterocarp forest. 

 Epiphytes are also more abundant, and include more cryptogams. Above 

 900 m. a montane forest is developed, exhibiting a single stratum of vegetation 

 some 10 m. high, and known as the "mossy forest" from the great abundance 

 of mosslike plants. 



As developed on Mt. Maquiling this last may be termed a Cyathea- A stroma 

 association from the two most prominent genera. The herbaceous ground 

 cover is dense; mosses, filmy and other ferns, Selaginella, orchids, and lianas are 

 abundant, many growing as epiphytes. Trees are low and contorted in habit. 

 Statistical analyses are made of all types of forest, the size of the trees as well 

 as their floristic relationship being given. Detailed data regarding rates of 

 growth of trees seem to show that they are proportional to the heights of the 

 various forest types. Stations were located in these forests, and at them 

 measurements were made of environmental factors, including temperature, 

 light, evaporation, rainfall, humidity, soil moisture, and wind velocity. Many 

 data were collected and are presented in tables and graphs. Some of the most 

 interesting conclusions based upon these are: (1) humidity is high at all 

 elevations, and the atmosphere is practically saturated at all times under 

 the montane forest; (2) temperature gradually decreases with rising eleva- 

 tion; (3) evaporation in all forests is much less than in the mesophytic forests 

 of the United States, and decreases rapidly with increasing altitude; (4) there 

 is a pronounced, although not severe, dry season; (5) only at low elevations 

 does there appear to be sufficient decrease in soil moisture during the dry 

 season to have any harmful effect on vegetation; and (6) the increase in her- 



