New genus and species, Quangnamia syncarpa (Hamamelidaceae), from central Vietnam

A new monotypic genus, Quangnamia (Hamamelidaceae), and its species, Q. syncarpa, discovered in central Vietnam are described and illustrated. Quangnamia syncarpa is evergreen treelet or tree with non-stellate indumentum on vegetative and floral parts, glabrous twigs and leaves, axillary inflorescences in form of spadix-like many-flowered heads, hermaphrodite, 5(6)-merous flowers, petals straight in bud, in open flowers greenish yellow, linear-lorate to linear, ribbonlike with straight and entire margins, lacking staminodes, 1-sporangiate anther thecae dehisced by a longitudinal slit, gynoecium syncarpous of two completely fused carpels, with inferior 2-locular ovary, each locule with 2 ovules placed on axial placenta, irregularly globular syncarpous infructescence consisting of few- to many 2-carpellate capsules, dorsoventrally flattened, broadly obovoid, entire or slightly retuse at apex, opening septicidally like bivalve shell, with two seed per carpel, and wingless seed. Morphological comparison of Quangnamia with related genera, and notes on the habitat, phenology, and conservation status of the new plant are provided and discussed.