Morphological Characterization and Conservation Assessment
Fresh samples of the putative new species, along with co-occurringR. banaoana , R. consueloae , and R. cf.aurantia , were collected and preserved in a 70% ethyl alcohol
solution. As with most taxonomic studies on Rafflesia, limited
material was available due to the rarity of the plant and poor
accessibility; however specimens were observed at several stages of
development (from bud to anthesis), both male and female. Specimens were
deposited in CAHUP, LBC, and PNH (abbreviations according to Thiers
2019). Dissected flowers were examined and the floral parts measured
using the ruler tool in Adobe Photoshop CC, calibrated using image
pixels. Material was compared with that of closely related species
(Table 1) . We follow the morphological species concept (Davis
and Heywood 1963; Knapp and Vorontsova 2016), which emphasizes the
importance of observable physical traits in identifying and categorizing
species.
The provisional conservation status of the species was assessed
following the criteria and categories of the IUCN (IUCN Standards and
Peititions Committee 2022). The extent of occurrence (EOO) and area of
occupancy (AOO) of the species were estimated with the Geospatial
Conservation Assessment Tool (Bachman et al. 2011).