IX, C, 5 Gates: Pioneer Vegetation of Taal Volcano 4l1l1 
The Themeda gigantea consocies—Themeda gigantea is a 
bunch-grass of fair size, nowhere spreading into a “sod” grass- 
land. The area occupied by this species is not nearly so ex- 
tensive as that occupied by Saccharum. Where the two grasses 
occur together, the structure of the vegetation is so open that 
there is no visible competition between them. Its distribution on 
Taal is rather limited; it occurs in greatest abundance on the 
steep slopes of Mount Binintiang Malaki, but is found also on 
Mount Balantoc on ridges radiating from the crater toward 
the northwest and in the rocky soil of the lake exposure of 
Mount Binintiang Munti. It occupies areas which have not been 
severely devasted. 
The plant itself forms bunches by the development of many 
buds from the central rootstock or a very few very short hori- 
zontal ones. The leaves which are about 0.5 meter in length 
are closely 2-ranked at the base. The many, open, loose, tall 
(from 1.5 to 2 meters) flower stems which develop in December, 
after the rainy season, give the area the appearance of the 
Sorghastrum nutans bunch-grass prairie in the northeastern 
Illinois sand-dune region. The bunches are rather well spaced, 
with from 1 to 1.5 meters of open ground between them. Even 
with this space between the bunches, when they grow on very 
steep slopes it appears from a little distance as if the entire 
ground were covered with grass. Apparently this makes a 
very open association, but this open association may be due 
largely to the extensively developed fibrous root system. Good 
control of the space is also evidenced in the scantiness of second- 
ary species. 
The association is best developed on the southern and western 
sides of Mount Binintiang Malaki, preferring the steeper, more 
rocky slopes, where it is very frequently associated with reddish 
rocks and iron in the soil. Apparently the consocies is in a 
relatively static condition, for it does not appear to be invading 
the open ground stretching out from the foot of Mount Binintiang 
Malaki, although the top of this peak has been reached. A heavy 
crop of seeds was set in December, 1913, but results are not yet in 
evidence. The seeds are too large to be widely distributed by 
ordinary winds, but were found in large numbers in April, 
1914, along stream courses and around the salt lake south of 
Mount Balantoc. 
Succession into Themeda is progressing, particularly on the 
northern slopes of Mount Binintiang Malaki, where conditions 
are much milder than those on the southern slopes. A number 
