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| Quangnamia K.S. Nguyen et Aver., Quangnamia syncarpa K.S. Nguyen, Aver., C.W. Lin, G.Q. Liu et H.H. Truong, in Nguyen, Averyanov, Lin, Liu, Truong, Pham, Maisak et Averyanova, 2024. Photos by H. H. Truong. |
Abstract
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.
Keywords: Altingiaceae, central Truong Son Range, endemism, plant diversity, plant taxonomy, Quang Nam Province
Quangnamia K. S. Nguyen et Aver., gen. nov.
Diagnosis. Quangnamia is most similar to Liquidambar, Mytilaria, and Trichocladus but distinct from them and all other known genera of Hamamelidaceae in capitate infructescence with capsules completely sunken into woody, globose torus, capsules dorsoventrally flattened, broadly obovoid, entire or slightly retuse at apex, without persistent style base, and the combination of the following features: evergreen, hermaphroditic tree; absence of stellate indumentums and staminodes; perulate vegetative buds; glabrous, simple, pinnate-nerved leaves; early caducous minute linear stipules; inflorescence in form of axillary spadix-like many-flowered head; bisexual 5(6)-merous flowers; petals straight in bud, ribbonlike in opened flowers; 1-sporangiate anther thecae dehisced by a longitudinal slit; syncarpous gynoeciumof 2 completely fused carpels; inferior 2-locular ovary, and 2 ovules per locule.
Type: Quangnamia syncarpa K. S. Nguyen, Aver., C. W. Lin, G. Q. Liu et H. H. Truong.
Monotype genus.
Etymology. Refers to the name of Quang Nam Province, where the type species was discovered.
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| Quangnamia syncarpa. Plant in natural habitat: A – flowering tree in the forest stands; B, C – flowering tree and treelet free standing in open place; D – flowering branches; E – flowering and fruiting branchlets; F – branch with young inflorescences; G – branch with full flowering inflorescences; H, I – close up full flowering inflorescences and individual inflorescence. Photos by H. H. Truong (A, C, photos from HH-QN 15 and 45) and L. Averyanov (B, D–I, photos from specimen CPC 3599), photo correction and design by L. Averyanov and T. Maisak. |
Quangnamia syncarpa K. S. Nguyen, Aver., C. W. Lin, G. Q. Liu et H. H. Truong, sp. nov.
Etymology. The specific epithet refers to syncarpous fruit forming entire lignified body.
Khang S. Nguyen, Leonid V. Averyanov, Che W. Lin, Guo Q. Liu, Hoang H. Truong, Van T. Pham, Tatyana V. Maisak and Anna L. Averyanova. 2024. New Genus and Species, Quangnamia syncarpa (Hamamelidaceae), from central Vietnam. Turczaninowia. 27(3); 159–176. DOI: 10.14258/turczaninowia.27.3.15 turczaninowia.asu.ru/article/view/16102
