ASPECTS OF GRASS VEGETATION 61 
The mountainous regions of Northern India, although within the 
temperate zone, produce a grass vegetation thoroughly inter- 
tropical in character, by reason of the torrential rains of the 
summer monsoon. Here flourish the noble.bamboos with ligneous 
culms, the taller kinds 50, 70, and even go feet high. The aver- 
age diameter of a 60 feet culm is 5 inches near the base. ‘These 
arborescent grasses, which cover the sides and tops of the moun- 
tains throughout the continent of India, form one of the peculiar as 
well as most striking features of Oriental scenery. Few objects 
present a more attractive sight in the wild forests of this country, 
than a clump of these beautiful plants, with their tall bending stems 
and delicate light green foliage.” The bamboos are abundant 
throughout the whole of S.E. Asia and the Malay Archipelago, 
varying much in habit; species with tall columnar culms, and 
profusely branched above, are common; others are slender, flexible, 
and semi-scandent, while many have a low, shrubby habit of growth. 
They frequently form jungles of vast extent, dense and impene- 
trable, with a uniform aspect (as there are seldom more than two 
ot three species in the same jungle) and a poor undergrowth, in 
consequence of deep shade. Most species flower simultaneously 
over large tracts of country, at intervals of a great many years ; 
they then die off, and their place is taken by seedlings, which grow 
with great rapidity. Bambusa arundinacea, the Great Bamboo, 
grows for the first 2-3 years as a clump of foliage, making only 
rootway ; then it begins to throw up its gigantic culms, 30-100 in 
a clump, which may grow 20-30 feet during a month. 
In the torrid zone, more particularly within the rainy belt, grasses 
give place, for the most part, to dense forests ; but wherever there 
is a tract of more open country, the great heat and moisture com- 
bine to produce a dense vegetation of tall herbaceous grasses (as 
distinguished from the bamboos with ligneous culms), which rise 
to 12 or 15, and in some cases to 20 feet, during the rainy season ; 
in the dry season they lie down. Grasses of this description are 
most abundant on the continent of Africa, in the Senaar, Sene- 
gambia, Guinea, and the equatorial lake region. The extremes 
of the two tropical seasons are most marked on the llanos of the 
Orinoco of South America ; during the rainy season, June-August, 
the plain is flooded, and a luxuriant growth of grass ensues ; in the 
dry season the soil is baked hard as stone, and the grasses are 
utterly parched up. Elevated regions of the torrid zone have a 
grass vegetation quite different to that of the low-lying plains. 
The high plateaux and mountain-slopes are clothed with a short 
green turf resembling that of the cool temperate zones. But on 
the Andes, and in other mountainous parts of inter-tropical 
America, jungles, forests, or belts of bamboo occur, as in the tropical 
countries of the East. 
The Panicacee are, generally speaking, tropical or warm temper- 
ate in their distribution, while the Poacee predominate almost to 
monopoly in the temperate and colder regions of both hemispheres, 
and are fairly well represented within the tropics. In reading the 
