Grasses produce large amounts of pollen and are among the main causes of pollen allergy worldwide. Quantification of the roles of individual grass species in airborne pollen is an important task, because morphologically indistinguishable pollen grains of different species may differ in allergenicity. This requires knowledge of the pollen production of individual grass species; however, accumulated data are insufficient in this respect. Attempting to fill this gap, we studied pollen production per inflorescence in 29 grass species which are widespread in Middle Russia and India. Pollen production per inflorescence is determined by the number of grains per anther, the number of flowers in a spikelet and the number of spikelets per inflorescence, with the latter parameter being the most variable. We support the hypothesis that pollen production per inflorescence differs significantly between annual and perennial grasses. The greater pollen production of perennials can be interpreted as a tendency to guarantee cross-fertilization of species with self-incompatibility. The inferred pollen/ovule (P/O) ratios suggest the occurrence of facultative xenogamy in all annuals and obligate xenogamy in most perennials in the present dataset, though some self-incompatible annuals exist outside our sampling. Earlier data indicated that the P/O ratio of the annual cereal crop rye (Secale cereale) is higher than in any annual or perennial species sampled here. A ratio of pollen production to seed set (P/S ratio) is suggested to be another efficient parameter in reproductive biology of grasses. We highlight a need for detailed studies of reproductive biology in grasses that include both pollen and seed production. We found a correlation between pollen production per anther and anther length. A rough approximation of c. 1000 pollen grains per 1 mm of the length of an anther provides an instrument for estimates of pollen production in plant communities.

The paper provides additions to the known diversity of Begonia in Vietnam and Laos. One species new to science from Lao PDR (B. vivipara) and three new species from Vietnam (B. aspersa, B. gracilifolia, B. maculifolia) are described. Three species (B. rotundilimba, B. versicolor, B. wenshanensis) are reported as new records for the flora of Vietnam. For each species, the information on ecology, phenology, estimated conservation status and distribution is presented, as well as the relevant taxonomic notes and analytical photographic illustrations.

The tribe Loteae (Papilioniodeae-Leguminosae), according to plastid data, belongs to the Robinioid clade, which also includes the tribes Robinieae and Sesbanieae. The tribe Loteae contains 16 genera and about two hundred seventy-five species, of which the plastid genomes of five species have been studied to date. The main objectives of our study were to obtain new information on the plastid genome structure of the Loteae representatives in order to assess plastid genome variability and reconstruct phylogenetic relationships within the tribe Loteae. We performed sequencing, assembly, structural and phylogenetic analyses of the Loteae plastid genomes. All assembled Loteae plastomes showed a quadripartite structure with an overall length ranging from 150,069 to 152,206 bp and showed relative stability of inverted repeat borders. The Loteae plastomes demonstrated full collinearity; the most variable sites of the studied plastomes were found in petN-trnC and rps16-accD spacers from the LSC region and in the ycf1 gene within the SSC. All inferred relationships attained maximal support with the Hippocrepis lineage separated first, followed by Coronilla and Anthyllis; Lotus is a sister group to the clade Acmispon + Ornithopus. In this study, completely resolved relationships representing a backbone of plastid phylogeny were produced. The obtained results demonstrated that plastid genomes in the tribe Loteae are structurally conservative in contrast to the closely related tribes Robinieae and Sesbanieae.

An updated checklist of the family Burmanniaceae in Cambodia, Laos and Vietnam is provided. The checklist comprises a single genus, Burmannia, and 15 species, of which one is fully autotrophic, six species are partially mycoheterotrophic, and eight species are fully mycoheterotrophic (non-photosynthetic). Burmannia itoana earlier known only from Japan and China is reported from Vietnam for the first time, based on our collections of this species from northern and southern parts of the country. The newly recorded species, as well as a selection of several other Vietnamese species of Burmannia, are illustrated with analytical photographs of floral structure. A key for identification of Burmannia in the countries of Eastern Indochina is presented.