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Eriocaulon is a genus of c. 470 aquatic and wetland species of the monocot plant family Eriocaulaceae. It is widely distributed in Africa, Asia and America, with centres of species richness in the tropics. Most species of Eriocaulon grow in wetlands although some inhabit shallow rivers and streams with an apparent adaptive morphology of elongated submerged stems. In a previous molecular phylogenetic hypothesis, Eriocaulon was recovered as sister of the African endemic genus Mesanthemum . Several regional infrageneric classifications have been proposed for Eriocaulon . This study aims to critically assess the existing infrageneric classifications through phylogenetic reconstruction of infrageneric relationships, based on DNA sequence data of four chloroplast markers and one nuclear marker. There is little congruence between our molecular results and previous morphology-based infrageneric classifications. However, some similarities can be found, including Fyson’s sect. Leucantherae and Zhang’s sect. Apoda . Further phylogenetic studies, particularly focusing on less well sampled regions such as the Neotropics, will help provide a more global overview of the relationships in Eriocaulon and may enable suggesting the first global infrageneric classification. Electronic supplementary material The online version of this article (10.1007/s10265-019-01129-3) contains supplementary material, which is available to authorized users.

BackgroundA new species, Begonia myanmarica, was discovered from Myanmar and herein documented. Characterized by a single developed wing in the ovary/fruit, this species would be assigned to sect. Monopteron (sensu Doorenbos et al. in The sections of Begonia including descriptions, keys and species lists: studies in Begoniaceae VI. Wageningen Agricultural University, Wageningen, 1998) that is known by B. griffithiana and B. nepalensis from the Himalaya. To confirm its sectional assignment, we conducted morphological, phylogenetic and cytological studies.ResultsMorphological observations indicated that B. myanmarica was distinguishable from the two known species of sect. Monopteron by the leaf shape and size, 1-locular ovary, parietal placentation and chromosome number. Molecular phylogenetic analysis using nrITS sequences showed that B. myanmarica was not allied with the clade of sect. Monopteron, though both were nested within sect. Platycentrum-sect. Sphenanthera clade.ConclusionsStudies of morphology, molecular phylogenetics and cytology support the recognition of the new species, Begonia myanmarica, which is fully described and illustrated. Our results also indicate that B. myanmarica is not closely related to species previously assigned to sect. Monopteron, suggesting that the fruit morphology of a single developed wing in the ovary/fruit characterizing sect. Monopteron is homoplasious.

Impatiens bokorensis, a new species of family Balsaminaceae from Phnum Bokor National Park in southwestern Cambodia, is described and illustrated. The species is similar to Impatiens patula, but is readily distinguished by the orbicular-obovate dorsal petal, shorter pedicels and larger seeds.

The species diversity of Orchidaceae is believed to be extremely high in Myanmar. Like in other plant groups, little basic inventory work has been done thus far. During floristic surveys conducted in Popa Mountain Park (Mandalay Region), Natma Taung National Park (Chin State), and in the Ywangan area (southwestern Shan State), we encountered two interesting orchid species which were determined to be new generic records in the flora of Myanmar. Thuniopsis cleistogama was previously considered endemic to Yunnan Province (China) and was only known from the type locality. However, here the species is newly reported from two localities in central and western Myanmar. Disperis neilgherrensis is known from several widely scattered localities in tropical and subtropical Asia. This tiny orchid species was discovered in the Ywangan area in the southwestern area of the Shan State of Myanmar. These two species will be valuable additions to the updated checklist of the orchids of Myanmar.