Rafflesia panchoana from Mt. Makiling, Luzon and R. manillana from Basey, Samar compared

Rafflesia manillana from  Basey, Samar (photo by RTD

                     Dr. M.Ragub and his research staff,  DENR Region VIII, Tacloban City.

                                Rafflesia panchoana from  Mt. Makiling, Laguna (previously

                                named R. manillana). (Photo by Prof.K. Mat Salleh, deceased)

The past ten years saw a dramatic increase in the number of Rafflesia species described  in the Philippines. From the original two species described in 1841 (R. manillana Teschem.) and in 1885 (R. schadenbergiana Goeppert)  eleven  more species were described  as new to science  starting in 2002 and the latest in 2011.

One of these species was described in  2007 from Mt. Makiling in Laguna. It was named  R. panchoana Madulid, Buot & Agoo in honor of  Juan V. Pancho,  Professor of Botany at the Institute of Biological Sciences, University of the Philippines at Los Banos. Earlier this species was often cited as R. manillana. apparently because of  its small size, (i.e. open flower about 15 to  20 cm diameter) similar to the Rafflesia from Basey, Samar.

Careful study of the original description (protologue) of R. manillana and detailed examination of actual specimens recently collected from the type locality in Basey, Samar revealed that the Rafflesia  from Samar is markedly different from the one in Mt. Makiling. The most obvious morphological difference between the two species is that in  R. manillana the diaphragm is conspicously  incurved and the orifice or mouth of the diaphragm is small that the inner side of the perigone tube cannot be seen from above. In  R. panchoana the  diaphragm is slightly upright, and  the opening or orifice is relatively wide, leaving the lower inner side of the perigone tube clearly seen  from above. The color of the diaphragm is also obviously different in that in R. manillana it is creamy white when the flower is newly opened, turning creamy orange when the flower matures whereas in  R. panchoana the color of the diaphragm is reddish brown when newly opened, turning deep reddish brown when older. There are other morphological differences between the two species such as the shape and location of the windows and the number of processes on the disk. These are discussed in the publications:  Madulid, D.A., Buot, I. and Agoo, E.M.G. Rafflesia panchoana, a new species from Luzon Island, Philippines. Acta Manillana 55:43-48 (2007) and Madulid, D.A. and Agoo, E.M.G. On the identity of Rafflesia manillana Teschem. (Rafflesiaceae). Philippine Scientist 44:57-70 (2007). D.A. Madulid