THE PHILIPPINE 
Journal of Science 
C. Botany 
(cS.: ' 
VOL. IX APRIL, 1914 No. 2 
AN ENUMERATION OF THE PLANTS OF GUAM 
By E. D. Merrill 
{From the Botanical Section of the Biological Laboratory, 
Bureau of Science, Manila, P. I.) 
(Concluded.) 
RUTACEAE 
CITRUS Linnaeus 
I have found it to be practically impossible to classify the material of 
the cultivated forms of this genus with any degree of satisfaction, and the 
difficulties have been well stated by Mr. Safford. There are a number of 
distinct forms in Guam, probably for the most part, if not all, introduced. 
CITRUS DECUMANA (Linn.) Murr. Syst. ed. 13 (1774) 580; Safford 
228. 
Citrus aurantium var. decumana Linn. Sp. PI. ed. 2 (1763) 1101. 
G. E. S. Jf8U, Ul, locally known as cahet magas. 
Throughout the Indo-Malayan region, cultivated in other hot countries. 
This species I consider to be one of the very few distinct ones in the 
genus. I do not consider it to be at all closely allied to the orange {Citrus 
aurantium L.). 
CITRUS AURANTIUM Linn. Sp. PI. (1753) 783; Safford 226. 
G. E. S. 396, McGregor A15, locally known as cahet. 
Cultivated in all tropical and subtropical countries, variable in fruit 
characters, a native of tropical Asia. 
Mr. Safford records the variety sinensis Linn., and the subspecies sapon- 
acea Safford from Guam. I cannot determine how Citrus sinensis can be 
distinguished from C. aurantium, and believe it to be only a form developed 
by cultivation. The subspecies saponacea is said by Mr. Safford to be wild 
in Guam, and to have non-edible fruits. I have seen no specimens of this 
form, but would suspect its alliance to be with Citrus hystrix rather than 
with C. aurantium. 
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