414 The Philippine Journal of Science 1921 
assured if selection is wisely made. By this method low-headed 
trees are also best obtained, but it has many drawbacks. 
In Nakorn Chaisri there are no nurseries where carefully 
selected strains of the best varieties of pummelo can be pur- 
chased. In Bangkok there are a few nurseries that profess to 
sell desirable stock. Each grower usually propagates his own 
trees, rarely more than he will need for his own planting. His 
theory is that the method of layering large branches is costly; 
and that from the fruiting branch, which he must sacrifice for 
his new tree, he could actually secure fruit which in one year 
alone would bring him a higher price than the new tree when 
sold as nursery stock. The average price for a layered plant 
is from 75 satang to 1 tical each, or 30 to 40 cents in United 
States currency. At this rate it is readily seen that the nursery. 
business will not prove profitable so long as this system of 
propagating is followed. Herein is found an inviting field for 
modern nursery methods. 
Marcottage is practiced in June, July, and August, after the 
rains have begun. A strip of bark is removed from the branch 
chosen. After a slight callus has formed, coconut fiber or spe- 
cially prepared earth is tied about the injured part. During 
dry weather this must be kept moistened. About one hundred 
days are necessary for the roots to form. The new plant is then 
removed from its parent and set out in a nursery bed or, more 
often, is planted directly in its permanent position. Branches 
chosen for this purpose are usually very much forked, and low- 
headed, spreading trees result (Plate 10, fig. 3). All growers 
consider these more desirable than the high-headed trees. 
FLOWERING, FRUITING PERIODS, AGE, AND YIELD 
The growers report that the Kao Pan, like most other citrus 
trees growing in this region, flowers in most abundance about 
four times each year. The largest number of flowers appears 
in June, at the beginning of the rainy season. This lot of flowers 
matures the largest crop of fruits. Five to six months are 
required to bring the fruits to maturity, and the largest crop 
is picked in November and sold direct or placed in storage. 
Trees of this variety are said to reach their maximum pro- 
duction when about fifteen years old and to have outlived their 
period of usefulness at about thirty years. It is difficult to 
arrive at any very definite figures regarding yield, though 
judging by the number of fruits on the trees during an off 
season, the trees of this variety must be very heavy bearers. 
