Aeschynanthus pentatrichomatus (Gesneriaceae), a new species of lipstick vine from the Banao Protected Landscape of Luzon Island in the Philippines

Aeschynanthus pentatrichomatus sp. nov. (Gesneriaceae), a new species from the tropical lower montane rain forests of the Banao Protected Landscape in Luzon Island in the Philippines is described and illustrated. Morphologically, it is most similar to A. batesii in having glabrous vegetative parts, polysepalous calyx, and distinctly mottled internal corolla throat and lobes. However, it differs from this species in its smaller lamina, longer peduncle, smaller calyx lobes, whitish pink external corolla tube, and presence of five tufts of trichomes near the basal portion of the internal surface of the corolla tube. Aeschynanthus pentatrichomatus differs from A. philippinensis by its externally whitish pink, internally white corolla tube with mottled maroon markings throughout the limb and lobes, smaller calyx lobes, and internal surface of corolla tube with five tufts of trichomes basally. Aeschynanthus pentatrichomatus sp. nov. is the 33rd species of lipstick vines to be described in the Philippines. The new species is provisionally assessed as Critically Endangered (CR) following the IUCN criteria.

Methods
An expedition in the municipality of Balbalan was conducted from 13–19 March 2020. During the expedition, an Aeschynanthus species was encountered that possessed distinct whitish pink corolla tube and mottled maroon markings on its corolla lobes. The plant was documented and collected. Ecological notes were also recorded. Spirit collection of the fragile parts followed the RBGE (2022) technique, and further dissections were carried out under stereomicroscopy (Olympus SZ51). 

Relevant taxonomic treatments and protologues of the species of Aeschynanthus were reviewed (Clarke 1883, Elmer 1908, Elmer 1910, Merrill 1915, Schlechter 1923, Merrill 1923, Burtt and Woods 1975, Mendum and Madulid 1995, Mendum 1999, Mendum 2001, Mendum et al. 2001, Weber 2004, Li and Wang 2005, Weber et al. 2013, Middleton 2007, Middleton 2009, Middleton 2016, Olimpos and Mansibang 2021, and Pelser et al. 2021), supported by examination of Aeschynanthus specimens deposited at A, BM, BRIT, E, GH, HBG, K, L, LY, MO, NY, US, VT, W, and Z; and PNH and PUH visited (see appendix). After thorough literature review and morphological comparison, it was clear that the species was different from all previously described Aeschynanthus species known in the Philippines and morphologically closest to the Sulawesi species A. batesii Mendum (2004: 324) (see diagnosis). The holotype was deposited at LBC; isotype was deposited in PUH.  The conservation status of the species was assessed following the International Union for Conservation of Nature (IUCN) Red List Categories and Criteria (IUCN Standards and Petitions Committee 2022).