yobs RUTACEAE 841 
Aegle glutinosa Merr. in Govt. Lab. Publ. (Philip.) 6 (1904) 12, 27 
(1905) 29, Fl. Manila (1912) 271. 
Limonia engleriana Perk. Frag. Fl. Philip. (1905) 163. 
Below glutinosa Skeels in U. S. Dept. Agr. Bur. Pl. Ind. Bull. 162 
(1909) 26. 
Luzon (Isabela to Tayabas). In thickets and secondary forests at low 
and medium altitudes. An endemic monotypic genus. 
Local names: Boyag (Tag.); kabtau-aso (Tag.); kabuyok (Ilk.); ka- 
lantan (Ibn.); tabég (Tag.); tab6ék (Tag.); talubok (Tag.) ; uratan (IIk.); 
malakabuyau (Tag.). 
20. CITRUS * Linnaeus 
CITRUS AURANTIFOLIA (Christm.) Swingle in Journ. Wash. Acad. 
Sci. 3 (1913) 465; Merr. Interpret. Herb. Amb. (1917) 296, Sp. 
Blancoanae (1918) 208. 
Limonia aurantifolia Christm. Pflanzensyst. 1 (1777) 618. 
Limonia acidissima Houtt. Nat. Hist. II 2 (1774) 444, non Linn. 
Limonia spinosum Mill. Gard. Dict. ed. 8 (1768), non Citrus spinosa 
Gmel. 
Citrus lima Lunan Hort. Jamaic. (1814) 451; Merr. Fl. Manila (1912) 
271. 
Citrus javanica Blume Bijdr. (1825) 140; Usteri Beitr. Ken. Philip. 
Veg. (1905) 118. 
Citrus acida Roxb. FI. Ind. ed. 2, 3 (1832) 390, non ? Pers. 
Citrus notissima Blanco FI. Filip. (1837) 607, ed. 2 (1845) 424, ed. 
3, 2 (1879) 406. 
Citrus limetta Risso var. aromatica Wester in Philip. Agr. Review 
8 (1915) 25. 
Citrus excelsa Wester in Philip. Agr. Review 8 (1915) 26, incl. var. 
davaoensis Wester 1. ec. 
Throughout the Philippines in the settled areas, usually planted. Pan- 
tropic, but native of the Indo-Malayan region, although apparently not a 
native of the Philippines. The lime. 
Local names: Bilolo (Tag.); dalaya’ (Ibn.); dalayap (Ilk.); dayap 
(Tag.) ; dulugot (Neg.); gorong-gérong (Ilk.); gugulo (If.); limén (Sp.) ; 
muyong (Bon.); sua (Bik.). 
* Following horticultural rather than strictly botanical usage the orange, 
the mandarin orange, the lime, the lemon, the citron, and the pomelo are 
here enumerated as species. It is highly probable that some of these fruits 
are of hybrid origin. In essential characters they are certainly no more 
distinct from each other than are some of the species recently proposed 
by Wester. I can see no really valid reasons for considering the sweet and 
sour oranges and the mandarin orange as other than forms of a single 
species. Without exception Wester’s species were based on cultivated 
plants and are, I believe, simple or complex hybrids or at most varieties of 
older species. It is a well-known fact that the various Citrus species 
freely hybridize. The only strictly native species in the Philippines is 
apparently Citrus hystrix DC. 
Citrus gaoganensis Hayata, C. limonelloides Hayata, C. depressa Hayata, 
C. tankan Hayata, C. natsudaidai Hayata, and C. kotokan Hayata, all 
recently described from Formosan material, Ic. Pl. Formos. 8 (1919) 
14-81, are, I believe, not true species but merely hybrids. 
