THE PHILIPPINE 
Journal of Science 
C. Botany 
VOL. VII. SEPTEMBER, 1912 No. 4 
THE RELATION OF RAFFLESIA MANILLANA TO ITS HOST. 
By William H. Brown. 
{From the Botanical Section of the Biological Laboratory, Bureau of Science, 
Manila, P. I.) 
The genus Rafflesia is particularly interesting on account of 
the large size of its flowers and the great reduction of its veg- 
etative parts. A flower of Rafflesia arnoldi R. Br., according to 
a description by Arnold in a letter to Robert Brown, measured 
a yard across and sprang from a root about the size of two 
fingers. Brown described the flower as parasitic on a species of 
Cissus and thought that part of the base was derived from the 
host. This opinion he later confirmed ^ and showed that the 
shoot of Rafflesia consisted of a short thick stalk terminating 
in a single large flower, around which, in its early stages, there 
were a number of bracts ; and that the base of the shoot was em- 
bedded in a cup-shaped mass of tissue formed by the host. The 
general relation of the parts of the flower and host is shown in 
figure 3 which represents an expanded flower bud of Rafflesia 
manillana. Robert Brown’s drawings show the young buds 
covered by the bark of the host. 
‘ Brown, R. An Account of a New Genus of Plants, named Rafflesia. 
Trans. Linn. Soc. 13 (1842) 201-234. 
^ Brown, R. Description of the Female Flower and Fruit of Rafflesia 
Arnoldi, with Remarks on its Afflnities ; and an Illustration of the Structure 
of Hydnora Africana. Trans. Linn. Soc. 19 (1845) 221-239. 
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