Hiding in plain sight: Two new species of Begonia section Petermannia (Begoniaceae) from the Philippines

With c. 1400 known species, Begonia is one of the largest plant genera. In order to address the evolution of Begonia we have produced maximum parsimony and maximum likelihood cladograms for 26S and ITS sequence data. Sequences were obtained from a total of 35 species of Begonia, one species of Symbegonia and two species of Datisca. The resulting phylogenetic hypotheses suggest that the most basal members of Begonia are from Africa, with American and Asian clades nested within the paraphyletic African Begonia. Despite marked morphological heterogeneity the endemic Begonia of Madagascar and the south Indian ocean islands form a monophyletic group. As currently circumscribed, Begonia is paraphyletic with the New Guinean endemic Symbegonia nested deeply within it and most closely related to species from the Asian section Petermannia. Analysis of a smaller ITS dataset, including three accessions of Symbegonia and nine accessions of Begonia section Petermannia, further suggests that Symbegonia is nested within section Petermannia, resolving within a monophyletic clade of New Guinean species. Morphological synapomorphies of Symbegonia are reviewed and this taxon is sunk into the genus Begonia, where it is given sectional status.

Two new species of Begonia section Petermannia from Zamboanga del Norte, Philippines are described and illustrated: Begonia amamampang and Begonia turugsoy. Begonia parvilimba was also rediscovered and an updated description is provided. All morphological characters and measurements were observed in the wild from living plants. This brings the record to a total of 16 Begonia species under this section found in the region of Zamboanga Peninsula making Zamboanga a center of diversity of section Petermannia in the Philippines. Notes on their ecology, distribution map and proposed conservation assessment are provided.

Material acquired on a recent expedition to Southeastern Sulawesi, Indonesia, presents an opportunity to reassess and provide an overview of the Begonia flora of the region. Eleven species are recognized including four new species described and illustrated here: Begonia incudiformicarpa, B. iskandariana, and B. tumburanoensis (all in Begonia section Jackia); and B. johntania (Begonia section Petermannia). The former three species are the first confirmed records of section Jackia on Sulawesi substantially extending the known eastern range limit of this section. In addition, an illustration and a lectotypification of Begonia flacca are presented, and an identification key to Begonia species in Southeastern Sulawesi is provided.

A new species of Begonia (Begoniaceae), B. varipeltata D.C.Thomas, is described from the Indonesian island of Sulawesi. It exhibits peltate leaves, which are rare in Begonia section Petermannia, to which it belongs.

Two new species of Begonia (Begoniaceae) from Bukit Tigapuluh National Park, Sumatra, Indonesia are described. Those are Begonia triginticollium Girm. belongs to Begonia section Bracteibegonia and Begonia dolichocarpa Girm. belongs to Begonia section Petermannia.

Two new species of Begonia (Begoniaceae), Begonia ozotothrix and Begonia hekensis, are described from the Indonesian island of Sulawesi. Both species belong to Begonia section Petermannia. Begonia ozotothrix is unusual amongst Asian Begonia in having branched trichomes on the stems, petioles and the abaxial lamina surfaces, and it is unusual amongst species of Begonia section Petermannia in having extremely compressed cymose-subumbellate male partial inflorescences.

A new Begonia section Petermannia species, Begonia corazoniae Naive, discovered in the forest ecosystems of Davao Oriental, southeastern Mindanao, Philippines, is herein described and illustrated. It closely resembles B. rieckei, but is easily recognized by having paniculate inflorescences with prominently winged ovary and capsule. A comprehensive morphological description, geographic distribution, ecology, phenology and a discussion of similar species is provided. In addition, we assessed this species as ‘Endangered' (EN B1(iii) + 2(iii)) following the criteria of the IUCN.

Begonia jamilahana Y.W.Low, Joffre & Ariffin is described and illustrated here as a new species based on a collection from Ladan Hills Forest Reserve, Tutong, Brunei Darussalam. This new taxon is closely related to B. conniegeriae S.Julia & Kiew and B. papyraptera Sands, but differs in a suite of morphological characters. Begonia jamilahana is placed in Begonia section Petermannia, the largest of all the sections recognised.

Taxonomy of the genus Begonia (Begoniaceae) in Mindanao, Philippines I: Begonia olganunezae, a new Begonia section Petermannia species discovered in the province of Bukidnon

A new species, Begonia hooveriana Wiriad., is described from Tanah Toraja in South Sulawesi. It belongs to Begonia section Petermannia and brings the total number of Begonia species native to Sulawesi to 43 species.

Taxonomy of the genus Begonia (Begoniaceae) in Mindanao, Philippines II: lectotypification of two Begonia section Petermannia species from the Zamboanga Peninsula

The pantropically distributed Begonia (Begoniaceae) is one of the most species-rich genera. Philippines is one of the diversity centers of Southeast Asian Begonia. In our 2012 field survey, three species of Begonia section Petermannia were collected in Barangay Sagubo, Municipality of Kapangan, Province of Benguet in the northern Luzon Island, Philippines. Our study on literatures and herbarium specimens suggests that these collections consist of B. crispipila, an unknown new species hereby we named B. balangcodiae, and the natural hybrid between them. Molecular analyses confirm that the former contributed the maternal genome while the latter provided the paternal genome. We name the natural hybrid B. × kapangan, which is the first natural hybrid reported in sect. Petermannia.