Heteromorphy in flowers has a profound effect on breeding patterns within a species, but little is known about how it affects reproductive barriers between species. The heterostylous genus Primula is very diverse in the Himalaya region, but hybrids there have been little researched. This study examines in detail a natural hybrid zone between P. beesiana and P. bulleyana. Chloroplast sequencing, AFLP (amplified fragment length polymorphism) markers and morphological comparisons were employed to characterize putative hybrids in the field, using synthetic F₁s from hand pollination as controls. Pollinator visits to parent species and hybrids were observed in the field. Hand pollinations were conducted to compare pollen tube growth, seed production and seed viability for crosses involving different morphs, species and directions of crossing. Molecular data revealed all hybrid derivatives examined to be backcrosses of first or later generations towards P. bulleyana: all had the chloroplast DNA (cpDNA) of this species. Some individuals had morphological traits suggesting they were hybrids, but they were genetically similar to P. bulleyana; they might have been advanced generation backcrosses. Viable F₁s could not be produced with P. bulleyana pollen on P. beesiana females, irrespective of the flower morphs used. Within-morph crosses for each species had very low (<10 %) seed viability, whereas crosses between pin P. bulleyana (female) and pin P. beesiana had a higher seed viability of 30 %. Thus genetic incompatibility mechanisms back up mechanical barriers to within-morph crosses in each species, but are not the same between the two species. The two species share their main pollinators, and pollinators were observed to fly between P. bulleyana and hybrids, suggesting that pollinator behaviour may not be an important isolating factor. Hybridization is strongly asymmetric, with P. bulleyana the only possible mother and all detected hybrids being backcrosses in this direction. Partial ecological isolation and inhibition of heterospecific pollen, and possibly complete barriers to F₁ formation on P. beesiana, may be enough to make F₁ formation very rare in these species. Therefore, with no F₁ detected, this hybrid zone may have a finite life span as successive generations become more similar to P. bulleyana.

Primula pingbaensis Na Zhang, X.Q.Jiang & Z.K.Wu, a new species of Primulaceae from Gaofeng Mountain of Pingba county, Guizhou, China, is described and illustrated. Morphological evidence supports P. pingbaensis as a member of P. sect. Petiolares on account of scape elongating, pedicels conspicuously thickening in fruit, and its capsule cracking irregularly round the top and crumbling away. Amongst the members of subsect. Davidii, the new species is characterized by having a uniquely smooth leaf blade due to inconspicuously raised veinlets and homostylous flowers with the style usually extending beyond the anthers. The distribution, phenology and conservation status of the new species are also provided.

Primula is a large genus of flowering herbs well known for their heterostyly. Currently few natural hybrids are known and reproductive barriers in this genus in the wild have received little attention. However, there is instance of hybridization between rare and widely-spread species, and conservation implications of such situation is poorly understood. In the present study, we investigated hybridization patterns and reproductive barriers between a wide spread species, Primula poissonii and a rare species P. anisodora, of which only three populations are currently known. Pollinator-mediated reproductive isolation was strong between parental species but not significant between hybrids and parental species. Hand pollination experiments showed significant reduction of both fruit- and seed-set for heterospecific pollination as compared with conspecific pollination for both parental species. Furthermore, hybrids had higher fruit- and seed-set when pollinated with P. anisodora pollen as opposed to P. poissonii pollen. Microsatellites identified backcrosses to P. anisodora in two of the three populations of P. anisodora, and additionally more individuals of P. anisodora showed introgression from P. poissonii than vice versa. These results provide evidence for potential genetic swamping of the P. anisodora populations, which could pose a serious threat for this locally endemic species.

Primula yanbianensis T.Shuai, Lei Cai & Z.K.Wu, a new species of Primulaceae from Sichuan, China, is described and illustrated. Morphological evidence supports P. yanbianensis as a member of P. sect. Cortusoides, which is characterised by lack of farina, generally well furnished with multicellular hairs, subrounded leaf blades are more or less lobed, with distinct petiole and a deeply cordate base and campanulate or narrowly campanulate calyx not accrescent after anthesis. The new species is characterised by having umbel in whorls of 1–2, scape usually lower than leaf clusters, bracts broadly ovate and rose to pink petals distinctly veined. The distribution, morphological comparison with closely-related species and conservation status of the new species are also provided.

A new species of Gesneriaceae, Oreocharis parviflora, is described and illustrated from Lanping County, northwestern Yunnan Province, China. The new species is morphologically similar to O. henryana in the shape and color of corolla, numbers of stigma, stamen and staminode characteristics, but it can be easily distinguished by the shape of leaf blade, indumentum characters of leaf blade, petiole, peduncle and pedicel.