Tuesday, May 26, 2015

[Botany • 2015] Goniothalamus flagellistylus Tagane & V. S. Dang • A New Species (Annonaceae) from Mt. Hon Ba, south Vietnam


Goniothalamus flagellistylus Tagane & V. S. Dang
(a) Leafy branch, (b) portion of abaxial leaf surface, (c) flowers on main trunk, (d) vertical section of flowers, (e) apertures between inner petals, (f–g) mature fruit on older blanch.

Abstract
A new species, Goniothalamus flagellistylus Tagane & V. S. Dang, sp. nov. from Hon Ba Nature Reserve in Khanh Hoa Province, South Vietnam is described and illustrated. This species is most similar to Goniothalamus tortilipetalus M.R.Hend., but distinct in having 308–336 stamens (vs. ca. 170–260) and ca.120 carpels (vs. ca. 50–100) per flower, and Stigma and pseudostyles ca.8.5 mm (vs. 4–4.5 mm) long.

Keywords: Annonaceae, Goniothalamus, Hon Ba Nature Reserve, Vietnam


Introduction
The genus Goniothalamus (Blume) Hook. f. & Thomson, with more than 130 species (Nakkhuntod et al. 2009, Tang et al. 2013), is one of the largest genera in the Annonaceae family. The species is characterized by mostly solitary, axillary and pendent flowers, two whorls of petals with inner petals smaller than the outer ones, the inner petals connivent and forming a distinctive dome over the stamens and carpels acting as a pollination chamber and stamens having apical connectives. Most species of Goniothalamus are distributed in lowland evergreen rain forests in Southeast Asia, extending from India to Australia, also in New Caledonia (Jessup 1986, Mat-Salleh 2001, Saunders 2002, Saunders 2003, Kundu 2006, Saunders and Munzinger 2007, Saunders and Chalermglin 2008, Turner and Saunders 2008). In Vietnam, the following 19 species of Goniothalamus are recorded: G. chartaceus H.L.Li, G. chinensis Merr. & Chun, G. donnaiensis Finet & Gagnep., G. elegans Ast, G. expansus Craib, G. gabriacianus (Baill.) Ast (Synonym, Goniothalamus saigonensis Pierre ex Finet & Gagnep.), G. gracilipes Bân, G. laoticus (Finet & Gagnep.) Bân, G. macrocalyx Bân, G. multiovulatus Ast, G. ninhianus Bân, G. takhtajanii Bân, G. tamirensis Pierre ex Finet & Gagnep., G. tenuifolius King, G. touranensis Ast, G. undulatus Ridl., G. vietnamensis Bân, G. wightii Hook.f. & Thomson and G. yunnanensis W.T.Wang (Finet and Gagnepain 1907, Hô 1999, Bân 2000).

During the botanical survey of Hon Ba Nature Reserve in South Vietnam, we encountered an undescribed species of Goniothalamus in Mt. Hon Ba at 400 m elevation. We here describe and illustrate this new species, Goniothalamus flagellistylus Tagane & V. S. Dang, sp. nov.

......

Figure 1. Goniothalamus flagellistylus sp. nov.
(a) Leafy branch, (b) portion of abaxial leaf surface, (c) flowers on main trunk, (d) vertical section of flowers, (e) apertures between inner petals, (f–g) mature fruit on older blanch, (h) holotype, (i) pedicel and sepals on old branch, (j) adaxial side of inner petal, (k) stamen, (l) carpel. (h–l) From Tagane et al. 1497.
Scale bars (i, j) = 1 cm, (k, l) = 1 mm. DOI: 10.3897/phytokeys.50.4427

Etymology: The specific epithet is in reference to its flexuous styles which is too long to insert straight in the pollination chamber that formed by the inner petals.



Shuichiro Tagane, Son Van Dang, Tetsukazu Yahara, Hironori Toyama and Hop Tran. 2015. Goniothalamus flagellistylus Tagane & V. S. Dang (Annonaceae), A New Species from Mt. Hon Ba, Vietnam. PhytoKeys. 50: 1-8. doi: 10.3897/phytokeys.50.4427

No comments:

Post a Comment