i9 , 4 Reinking and Groff: Siamese Seedless Pummelo 421 
very small abortive seeds., will bear fruits in November which 
often have large mature seeds, frequently considerable in num- 
ber. The contention is that there are no individual trees which 
always carry seedless fruits, but fruits of the same tree vary 
greatly. The fact, that the same trees that produce seedless 
fruits at times are said to produce seedy fruits during other 
portions of the year, destroys the common theory that the Kao 
Pan is a true seedless variety. Moreover, when taken to other 
places it usually becomes seedy. There can be little question, 
however, that this variety has a greater tendency to seedless- 
ness than many others. A strictly seedless strain might be se- 
cured through an extended study of tree and bud variation. 
In most of the fruits there is always some evidence of rudimen- 
tary seeds. 
CLASSIFICATION 
From the general description of this fruit and the tree upon 
which it grows, the likeness of some of its characteristics to 
those of the orange is apparent, though somewhat remotely 
hidden. This might possibly raise a question as to whether 
the variety might possibly be a natural hybrid of Citrus maxima 
(Burm.) Merr. ( Citrus grandis Osbeck), the pummelo, and 
Citrus sinensis Osbeck, the common or sweet orange; or, at 
least, it might possibly possess some orange characters. Cer- 
tainly, the nature of the tree, the shape of the leaf and the fruit, 
and the size and the shape of the oil cells would indicate a 
tendency in this direction ; but this fruit is rightly classed as a 
variety of pummelo. 
DISEASES 
A study of citrus diseases of Siam was made during June and 
July and later published . 10 Though the season was 1 still dry, it is 
believed that the major diseases were encountered. The se- 
verity of these is undoubtedly much greater during the rainy 
season, and some maladies, other than those noted by us, may 
be present. 
Citrus canker is the same in general formation on the various 
species and varieties of citrus growing in Siam as on those 
growing in the Philippine Islands. Citrus maxima (Burm.) 
Merr. (C. grandis Osbeck) and C. aurantifolia (Christm.) Swin- 
10 Reinking, Otto A., Citrus diseases of the Philippines, Southern China, 
Indo-China and Siam, Philip. Agri. 9 (1921) 121-179. 
181287 3 
