In a new article published in Check List (https://doi.org/10.15560/17.3.917), museum researchers co-wrote a new record of the presence of Hoya sipitangensis in the Philippines, specifically, Palawan Island. The team included UPLB assistant professor Marjorie D. delos Angeles and MNH research associate Cristian C. Lucañas and curator Prof. Annalee S. Hadsall.

According to Hadsall, H. sipitangensis was only previously reported from where they were originally found – Sipitang, Sabah, Borneo; and Seria, Belait, Brunei.

“In Borneo, it was discovered in 2002 and named as H. sipitangensis; while in Brunei, it was first named as H. yapianum in 2010” she clarified. In 2016, however, H. yapianum was synonymized to H. sipitangensis on the basis that “the differences are part of the natural variation of the latter.”

“While on fieldwork in Palawan, we saw H. sipitangensis among branches of trees which formed dense canopies,” Prof. Marjorie D. delos Angeles, a botanist from the UPLB Institute of Biological Sciences and lead author of the new record said.

“These types of canopies create shady and moist understories where Hoyas can thrive well,” explained Hadsall.

According to the researchers, flora from Borneo could possibly be found in Palawan and vice versa as it was observed by other scientists that there is an influence of Bornean biogeography on the island of Palawan.

In 1990, Van-Wright wrote that “Palawan is a distinct biogeographic zone due to its historical connections with the Greater Sunda Shelf.” In 2017, a study by Santiago and Buot noted that two species of Hoya from Palawan are shared with the Sunda shelf, which includes Malay Peninsula, Sumatra, Borneo, Java, and other surrounding islands.

“With more rigorous fieldwork and greater coverage, it is highly possible that we may still find more Hoyas in Palawan that are shared with our neighbors,” de los Angeles said.

The H. sipitangensis collected by de los Angeles from Palawan was compared with original descriptions of H. sipitangensis Kloppenb. & Wiberg and H. yapiana Kloppenb. from the University of California Herbaria. The voucher specimen was deposited at the UPLB Museum of Natural History’s Botanical Herbarium.

The findings and the scientific publication were an output of the research project “Ecology and Systematics of Pteridophytes in the Puerto Princesa Subterranean River National Park (PPSRNP)” headed by delos Angeles in collaboration with Protected Area Superintendent Elizabeth Maclang and Forest Ranger Augusto Asis of the PPSRNP.