NATURAL AREAS AND REGIONS 



711 



hotter parts a number of interesting 

 algae and bacteria, some of them occur- 

 ring at temperatures as high as 60C. 

 In the areas saturated with the cooled 

 salt water are plants usually associated 

 with the seashore swamps, such as the 

 large, coarse fern, Achrostichum aureum 

 L. The salty areas are too restricted 

 to support characteristic salt water 

 animal life. 



BEACH 



The pioneer vegetation of the drier, 

 more sandy lake shores is dominated by 

 two cosmopolitan species of vines, the 

 pataning dagat or "Sea bean," Canavalia 

 lineata (Thunb.) DC, and Ipomea pes 

 caprae L. Both of these are widely 

 distributed on exposed shore lines 

 throughout the tropics. 



GRASSLANDS AND OPEN BRUSH 



The vegetation of the abandoned 

 fields of the lowlands consists largely of 

 introduced forms and species of very 

 wide distribution throughout the trop- 

 ics. This area, extending from the lake 

 to well into the foothills of Mount 

 Makiling, is therefore primarily of 

 interest to students of plant succession, 

 for many of the steps from the cultivated 

 fields to high forest may be seen here. 

 The first growth immediately after an 

 area is abandoned is composed of herbs, 

 herbaceous vines and grasses : Ageratum 

 conyzoides L., Cor chorus acutangulus 

 Lam., Amaranthus spp., Mimosa pudica, 

 L., Synedrella nodiflora (L.) Gaertn.; 

 Paspalum conjugatum Berg., Cynodon 

 dactylon (L.) Pers. and Eleusine indica 

 (L.) Gaertn., are some of the com- 

 monest forms. These and most of the 

 grassland species are either introduced 

 or widely distributed species, there being 

 comparatively few endemic forms. A 

 few low shrubs also appear early in the 

 revegetation of cleared areas; notably 

 Blumea balsamifera (L.) DC., Sida 

 retusa L, Urena lobata L. and Desmodium 

 spp. 



A second step is the conversion of the 

 weed areas into more nearly pure grass, 

 by the entry and spread of such rank 



grasses as Cogon, Impereta cylindrica 

 (L.) Beauv., talahib, Saccharum sponta- 

 neum L., etc. These are usually ac- 

 companied by such shrubs as Flemingia 

 strobilfera (L.) R. Br., Mallotus muri- 

 catus, Mussaenda phillipica L. C. Rich, 

 with its conspicuous white leaflike 

 floral bracts and Tabernaemontana pan- 

 dacaqui Poir., an endemic species with 

 clusters of conspicuous white, jasmine- 

 like flowers and brilliant red and yellow 

 seed pods. Among these are the fore- 

 runners of the arborescent flora; several 

 introduced forms, such as aroma, Acacia 

 farnesiana (L.) Willd., Psidium guajava, 

 Linn., Averrhoa bilimbi, L.,A. carambola, 

 L., and Laucaena glauca (L.) Benth., 

 all of American origin; Bauhinia mala- 

 barica Roxb., Leea manillensis Walp. 

 and Laportea spp., the giant stinging 

 nettles. 



These grasslands or "Congonales" 

 are of great extent in the Philippines, 

 and indeed through the entire Indoma- 

 layan region. They are a result of a 

 system of temporary and shifting cul- 

 tivation by the Malays, who with 

 their primitive implements are poorly 

 equipped to combat in their fields such 

 vigorous grasses as the cogon, Imperata 

 cylindrica (L.) Beuv. These abandoned 

 cogonales would quickly grow up to 

 trees, as such areas are doing around 

 the college lands, if it were not for 

 frequent fires, which destroy all but the 

 more resistant trees, such as the aroma, 

 Acacia Farnesiana (L.) Willd., the 

 binayuyu, Antidesma ghaesembilla 

 Gaertn., and the alibangbang, Bauhinia 

 malabarica Roxb., and even these are 

 stunted by the frequent burning, as 

 the natives usually fire these patches 

 three or four times a year. 



The next development in the suc- 

 cession is the brush forest or "Parang," 

 composed of numerous species of small, 

 rapid-growing trees, such as Macaranga 

 spp., Mallotus spp., labayo, Melochia 

 umbellata Stapf., Premna spp., Ficus 

 nota Merr. (tibig), Ficus hauili Blanco 

 (Hauili), Ficus ulmifolia Lam. (isis), 

 Ficus pseudopalma Blanco, and bayag- 

 usa Voacanga globosa Merr. Among 



