126 
AMERICAN JOURNAL OF BOTANY 
[Vol. io, 
2. The time of the year when set, the age of the tree, and climatic and 
soil conditions are all factors determining the growth rate of the fruits. 
Some fruits may mature in 7 or 8 months, while others growing on the same 
tree may require as much as 14 months in which to mature. 
3. Lemons may actually decrease in size while still attached to the tree, 
in consequence of the withdrawal of water from them by the leaves. This 
withdrawal of water from the fruits by the leaves may result in the collapse 
of at least a portion of the tissue in the stylar end of the fruit. 
4. The wilting coefficient of the soil as indicated by lemon leaves can 
not be considered a safe criterion as to whether or not the lemon fruits are 
suffering from a lack of water. 
5. There is practically no difference between the water contents of the 
two ends of the normal lemon. 
6. As the lemon enlarges, its water content increases, but this increase 
is much more rapid up to the time that it is about 3.8 cm. in diameter than 
from that time to maturity. 
7. The size of the lemon is not necessarily proportional to the percentage 
of water it contains. In September a lemon 1.90 cm. in diameter may have 
a much lower water content than a lemon 1.27 cm. in diameter in December. 
8. Mature lemons may show considerable variation in water content. 
The range in this series of experiments was from 88.20 to 92.14 percent. 
9. While the total acid content of the lemon increases rapidly as it 
approaches maturity, the true acidity increases very little after the lemon 
has reached a diameter of about 3.8 cm. 
10. There are quite wide variations, but the average of a large number 
of stylar and stem ends of normal lemons shows the mean acidity to be 
substantially the same for each. 
11. Mature lemons of practically the same age and size have a compara¬ 
tively wide range of acidity. 
LITERATURE CITED 
1. Bartholomew, E. T., Barrett, J. T., and Fawcett, H. S. Internal decline of lemons I. 
Distribution and characteristics. Amer. Jour. Bot. 10: 67-70. 1923. 
2. Clark, W. M., and Lubs, H. A. The colorimetric determination of hydrogen ion con¬ 
centration and its application in bacteriology. Jour. Bact. 2: 191-236. 1917. 
3. Coit, J. E., and Hodgson, R. W. An investigation of the abnormal shedding of young 
fruits of the Washington navel orange. Univ. Cal. Pub. Agr. Sci. 3: 283-368. 1919. 
4. Hodgson, R. W. Some abnormal relations in citrus trees of the arid southwest and their 
possible significance. Univ. Cal. Pub. Agr. Sci. 3: 37-54. 1917. 
5. Livingston, B. E., and Brown, W. H. Relation of the daily march of transpiration to 
variations in the water content of foliage leaves. Bot. Gaz. 53: 309-330. 1912. 
6. Reed, H. S. Certain relationships between the flowers and fruits of the lemon. Jour. 
Agr. Res. 17: 153-166. 1919. 
7. Renner, O. Experimentelle Beitrage zur Kentniss der Wasserbewegung. Flora 103: 
171-247. 1911. 
8. Wehmer, C. Die Pflanzenstoffe. Pp. 937. Jena, 1911. (See p. 399.) 
