Goniothalamus sukhirinensis Leerat., Chalermglin & R.M.K.Saunders, 2021
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publication ID |
https://dx.doi.org/10.3897/phytokeys.184.73210 |
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persistent identifier |
https://treatment.plazi.org/id/5FBB87FB-3873-581A-A547-6576F6E21FB0 |
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scientific name |
Goniothalamus sukhirinensis Leerat., Chalermglin & R.M.K.Saunders |
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sp. nov. |
Goniothalamus sukhirinensis Leerat., Chalermglin & R.M.K.Saunders sp. nov.
Figs 5 View Figure 5 , 6 View Figure 6
Diagnosis.
Goniothalamus sukhirinensis resembles G. macrophyllus and G. scortechinii , but is distinguished by its densely hairy shoots, numerous secondary veins (32-40 pairs per leaf), generally longer pedicels (flowering: 12-18 mm; fruiting: 20-25 mm), larger outer petals (34-37 by 18-22 mm), larger monocarps (20-27 by 9-13 mm) that are densely hairy, and longer seeds (13-17 mm).
Types.
Thailand: Narathiwat: Sukhirin, Ban Yade village, Ma Mong subdistrict, 167 m alt., 6 March 2021, C. Leeratiwong 21 - 1708 (holotype PSU; isotypes BKF, KKU).
Description.
Shrubs to small trees, to 4 m. Young branches densely appressed-pubescent. Leaf laminas 28-50 by 7-16 cm, length/width ratio 3.1-4, (lanceolate-)oblong, apex generally acuminate to caudate (rarely acute to obtuse), acumen 7-20 mm long, base broadly cuneate, subcoriaceous, glabrous abaxially (sparsely hairy over midrib), sparsely pubescent adaxially (densely hairy over veins); midrib strongly prominent abaxially, sunken adaxially; secondary veins 32-40 pairs, plane adaxially; tertiary veins percurrent, distinct, lacking a ‘granular’ appearance abaxially; petioles 20-30 mm by 4-6 mm, densely pubescent. Flowers solitary or paired, often on main trunk (cauliflorous), rarely on older branches (ramiflorous), pendent; flowering pedicels 12-18 mm long, densely hairy; pedicel bracts ovate-triangular, 2.5-3 by 1-1.5 mm. Sepals greenish-pink, broadly ovate, 7-9.5 by 7.5-10 mm, basally connate (2.5-3 mm from base), apex acute, moderately hairy abaxially, sparsely hairy adaxially, venation indistinct. Outer petals greenish-yellow when young, whitish-yellow (green at claw) when mature, 34-37 by 18-22 mm with 3-5 mm-long claw, length/width ratio 1.6-1.9, fleshy, (lanceolate-)ovate, apex acuminate, densely hairy abaxially, moderately hairy adaxially with velutinous basal region facing apertures between inner petals, midrib raised adaxially, venation indistinct ab- and adaxially. Inner petals 13-15 by 7-8 mm with 2-3 mm long claw, length/width ratio 1.8-1.9, ovate-lanceolate, densely hairy abaxially, sparsely hairy distally adaxially, yellowish-green when young, pinkish-orange to reddish-brown when mature, apex acuminate, lacking a glabrous lasteral flange on the inner petal claws. Stamens numerous, oblong, 2.5-3.7 mm long; connectives apiculate, papillate. Carpels 11-20 per flower, ovary oblong, 2-3 mm long, with white hairs; stigma and pseudostyle 2-2.5 mm long, stigma funnel-shaped, hairy. Fruits sometimes with persistent calyx, immature fruits brownish-green, mature fruits not seen; fruiting pedicels 20-25 by 2-3.5 mm, sparsely hairy. Monocarps 5-14 per fruit, single-seeded, 20-27 by 9-13 mm, length/width ratio 2-2.7, (obovoid-)ellipsoid, apex apiculate, apicule 5-8 mm long, smooth, densely hairy, glossy, pericarp 1-2 mm thick, stipes 7-15 by 2-3 mm, densely hairy. Seeds 13-17 by 8-10 mm, length/width ratio 1.6-1.7, ellipsoid, testa densely villose, slightly rugose.
Phenology.
Flowering and fruiting in February and March (based on limited data).
Distribution and habitat.
Endemic to Narathiwat Province, Peninsular Thailand (Fig. 4 View Figure 4 ). Growing in shady and moist areas of tropical rainforests; 167-200 m alt.
Etymology.
From the name Sukhirin, Narathiwat Province.
Local name.
Ratchakhru khao (ราชครูขาว) (Narathiwat).
Additional specimen examined (paratype).
Thailand: Narathiwat Province: Sukhirin District, Ban Yade village, Ma Mong subdistrict, 200 m alt., 28 February 2021, C. Leeratiwong 21 - 1707 (PSU).
Discussion.
As with the previous species, G. sukhirinensis is yet to be included in a molecular phylogenetic analysis but has strong morphological affiliations with a clade that comprises G. loerzingii R.M.K.Saunders, G. macrophyllus , G. scortechinii , G. uvarioides and G. wrayi King (nested within clade ‘A1a’ sensu Tang et al. 2015a, b). The morphological characteristics of this clade are detailed under G. roseipetalus , above.
Goniothalamus sukhirinensis resembles G. macrophyllus and G. scortechinii , but differs in several key characters: densely hairy shoots (vs glabrous to medium-hairy); numerous secondary veins (32-40 pairs per leaf, vs 12-23 in G. macrophyllus and [18-]21-26[-32] in G. scortechinii ); generally longer flowering pedicels (12-18 mm, vs 5-11.5 mm in G. macrophyllus and 8-13 mm in G. scortechinii ); larger outer petals (34-37 by 18-22 mm, vs 10-28 by 4.5-11.5 mm in G. macrophyllus and 20-33 by 8-14 mm in G. scortechinii ); longer fruiting pedicels (20-25 mm, vs 7-19 in G. macrophyllus and 8-20 mm in G. scortechinii ); larger monocarps (20-27 by 9-13 mm, vs 8-15 by 7.5-10 mm in G. macrophyllus and 9-18 by 6-10 mm in G. scortechinii ) that are densely hairy (vs subglabrous to medium-hairy); and longer seeds (13-17 mm, vs 8.5-12 mm in G. macrophyllus and 8-11 mm in G. scortechinii ). Goniothalamus sukhirinensis also differs from G. macrophyllus as its leaves lack the fine ‘granular’ appearance of the latter species (due to the immersion of tertiary and higher-order veins: Saunders, 2002), and has longer monocarp stipes (7-15 mm, vs up to 1.8 mm in G. macrophyllus ).
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