Ma et al. study a natural hybrid zone between two heterostylous primrose species, Primula beesiana and P. bulleyana, and find that all hybrid derivatives examined are backcrosses of first or later generations to P...
Mycorrhizal fungi are needed for germination and seedling establishment in orchids, so associations may be involved in determining hybridization between species. Jacquemyn et al. show that in three species of the genus...