taxonID	type	description	language	source
B74CF5F9FD2054598278C7F6882AC5E8.taxon	description	Figs 4, 6 G – I	en	Chokrassameehirun, Siwakorn, Kraichak, Ekaphan, Jaruwattanaphan, Tassanai (2025): A new species, Didymoglossum radiatum (Hymenophyllaceae), and two new records with note to the genus Didymoglossum Desv. from Thailand. PhytoKeys 261: 59-75, DOI: 10.3897/phytokeys.261.157609
B74CF5F9FD2054598278C7F6882AC5E8.taxon	diagnosis	Diagnosis. This species is frequently misidentified as D. sublimbatum (Fig. 6 J – L), but D. henzaianum has notably smaller fronds, typically about 1.5 cm long. The sterile fronds are round or linear, while fertile fronds range from ovate to spatulate. In contrast, D. sublimbatum has larger fronds (usually 2 – 3 cm long) that are oblong to lanceolate.	en	Chokrassameehirun, Siwakorn, Kraichak, Ekaphan, Jaruwattanaphan, Tassanai (2025): A new species, Didymoglossum radiatum (Hymenophyllaceae), and two new records with note to the genus Didymoglossum Desv. from Thailand. PhytoKeys 261: 59-75, DOI: 10.3897/phytokeys.261.157609
B74CF5F9FD2054598278C7F6882AC5E8.taxon	description	Description. Rhizomes: long, creeping, slender, densely covered with short brown hairs. Stipes: very short, less than 2 mm long, terete in basal portion, sparsely covered with dark brown multicellular hairs. Fronds: entire to slightly lobed, with various shapes, round to ovate or linear to spatulate, 0.5 – 2 cm long, 0.5 cm broad, moderately acute to round at apex, cuneate at base, margin entire or slightly undulate. False veinlets: many, long, some false veins connected to main veins, usually 5 – 8 cells between adjacent false veins, apex of false veins usually falcate, forming sub-parallel to margin and connected to upper ones but not continuous. Sori: solitary, sunk in the apical segment, usually 1 – 2 sori per frond. Involucres: obconic, broadly dilated at the mount of involucres. Receptacles: filiform, long exserted.	en	Chokrassameehirun, Siwakorn, Kraichak, Ekaphan, Jaruwattanaphan, Tassanai (2025): A new species, Didymoglossum radiatum (Hymenophyllaceae), and two new records with note to the genus Didymoglossum Desv. from Thailand. PhytoKeys 261: 59-75, DOI: 10.3897/phytokeys.261.157609
B74CF5F9FD2054598278C7F6882AC5E8.taxon	distribution	Distribution and habitat. India, Myanmar, Vietnam, Thailand, and Malesia (Peninsular Malaysia). Epilithic near streams.	en	Chokrassameehirun, Siwakorn, Kraichak, Ekaphan, Jaruwattanaphan, Tassanai (2025): A new species, Didymoglossum radiatum (Hymenophyllaceae), and two new records with note to the genus Didymoglossum Desv. from Thailand. PhytoKeys 261: 59-75, DOI: 10.3897/phytokeys.261.157609
49912CD1587F5AD0BD5CD2FDF6DC1A86.taxon	description	Figs 5, 6 M – O	en	Chokrassameehirun, Siwakorn, Kraichak, Ekaphan, Jaruwattanaphan, Tassanai (2025): A new species, Didymoglossum radiatum (Hymenophyllaceae), and two new records with note to the genus Didymoglossum Desv. from Thailand. PhytoKeys 261: 59-75, DOI: 10.3897/phytokeys.261.157609
49912CD1587F5AD0BD5CD2FDF6DC1A86.taxon	diagnosis	Diagnosis. Didymoglossum mindorense resembles D. bimarginatum (Fig. 6 P – R) but differs in having deeply lobed segments and fewer false veinlets, which are more widely spaced.	en	Chokrassameehirun, Siwakorn, Kraichak, Ekaphan, Jaruwattanaphan, Tassanai (2025): A new species, Didymoglossum radiatum (Hymenophyllaceae), and two new records with note to the genus Didymoglossum Desv. from Thailand. PhytoKeys 261: 59-75, DOI: 10.3897/phytokeys.261.157609
49912CD1587F5AD0BD5CD2FDF6DC1A86.taxon	description	Description. Rhizomes: filiform, long-creeping, densely covered with dark brown hairs. Stipes: short, to 5 mm long. Fronds: less than 3 cm long, usually 2 – 2.5 cm long, c. 1.2 cm broad, entire to pinnately lobed, round at apex, attenuate to broadly cuneate at base. Costa: glabrous, obsolete near apex. Submarginal false veinlets: continuous with 1 – 2 rows of normal cells outside. False veinlets: long, distantly placed, connecting and running from main veins to submarginal ones, distancely placed, usually 6 – 10 cells between adjacent false veins. Lobes: obtuse at apex, usually 0.5 – 0.7 (– 1) cm long, slightly undulate. Sori: solitary, sunk in lobes. Involucres: tubular, with a distinctly dilated mouth. Receptacles: long exserted, broken when aged.	en	Chokrassameehirun, Siwakorn, Kraichak, Ekaphan, Jaruwattanaphan, Tassanai (2025): A new species, Didymoglossum radiatum (Hymenophyllaceae), and two new records with note to the genus Didymoglossum Desv. from Thailand. PhytoKeys 261: 59-75, DOI: 10.3897/phytokeys.261.157609
49912CD1587F5AD0BD5CD2FDF6DC1A86.taxon	distribution	Distribution and habitat. Thailand, Malesia (Borneo, Philippines, New Guinea), Solomon Islands, Australia (NE Queensland). Epiphyte or epilithic near streams at lower elevations, usually growing at the base of the tree.	en	Chokrassameehirun, Siwakorn, Kraichak, Ekaphan, Jaruwattanaphan, Tassanai (2025): A new species, Didymoglossum radiatum (Hymenophyllaceae), and two new records with note to the genus Didymoglossum Desv. from Thailand. PhytoKeys 261: 59-75, DOI: 10.3897/phytokeys.261.157609
E277DE2D77A650158C43F9DD334C90DD.taxon	description	Figs 2, 3, 6 A – C	en	Chokrassameehirun, Siwakorn, Kraichak, Ekaphan, Jaruwattanaphan, Tassanai (2025): A new species, Didymoglossum radiatum (Hymenophyllaceae), and two new records with note to the genus Didymoglossum Desv. from Thailand. PhytoKeys 261: 59-75, DOI: 10.3897/phytokeys.261.157609
E277DE2D77A650158C43F9DD334C90DD.taxon	diagnosis	Diagnosis. Didymoglossum radiatum is similar to D. tahitense (Fig. 6 D – F) and D. hildebrandtii (Kuhn) Ebihara & Dubuisson in having peltate fronds but differs in several key characters. In D. tahitense and D. hildebrandtii, the false veinlets are branched, forming dichotomous branching in almost all veins (Fig. 6 E). In contrast, the false veinlets of D. radiatum are parallel, unconnected from the inner base of the false veins throughout their entire length. The frond diameter of D. radiatum is smaller (c. 1.5 cm) compared to D. tahitense (c. 1 – 3 mm) (Fig. 6 D). The sori of D. radiatum are raised, solitary, c. 2 mm long, usually sunk in the deep notch of the fronds. In comparison, the sori of D. tahitense can reach up to 4 mm in length and are situated in shallow marginal notches (Fig. 6 F), whereas D. hildebrandtii has multiple sori per frond. Additionally, D. hildebrandtii is distributed in the Comoros and East Africa, unlike D. tahitense, which occurs sympatrically with D. radiatum in the Malesian region. A closely related species, D. beccarianum, is readily distinguished by its stipitate fronds, pinnate arrangement of false veinlets, and sori in the apical notch of fertile fronds.	en	Chokrassameehirun, Siwakorn, Kraichak, Ekaphan, Jaruwattanaphan, Tassanai (2025): A new species, Didymoglossum radiatum (Hymenophyllaceae), and two new records with note to the genus Didymoglossum Desv. from Thailand. PhytoKeys 261: 59-75, DOI: 10.3897/phytokeys.261.157609
E277DE2D77A650158C43F9DD334C90DD.taxon	description	Description. Rhizomes: long-creeping, slender, c. 0.2 – 0.3 mm in diameter, densely covered with dark brown hairs, tightly attached to substrate. Fronds: sessile, peltate, c. 1 – 1.5 cm in diameter, circular to elliptic, margin of fronds densely covered with short dark brown hairs. False veinlets: dense, connected to joint of fronds, parallel and not connected to each other, running straight to margin, obsolete near apex, densely covered with dark brown hairs underside, and tightly attached to substrate. Sori: solitary, usually one per frond, sunk in deeply notch, borne on main veins running straight from joint of frond, raised, ascending to erect, anticlinal to substrate. Involucres: tubular, c. 2 – 2.5 mm long, fully emerging from fronds, wings very narrow, forming ridge in appearance, broadly dilated at apex. Receptacles: filiform long exerted.	en	Chokrassameehirun, Siwakorn, Kraichak, Ekaphan, Jaruwattanaphan, Tassanai (2025): A new species, Didymoglossum radiatum (Hymenophyllaceae), and two new records with note to the genus Didymoglossum Desv. from Thailand. PhytoKeys 261: 59-75, DOI: 10.3897/phytokeys.261.157609
E277DE2D77A650158C43F9DD334C90DD.taxon	distribution	Distribution and habitat. This species is only known from Thailand, adjacent to Malaysia. Sparse populations were discovered near the type locality in a nationally conserved area. Epiphytic or epilithic habit, usually near the streamlet at low elevations of lowland evergreen forest.	en	Chokrassameehirun, Siwakorn, Kraichak, Ekaphan, Jaruwattanaphan, Tassanai (2025): A new species, Didymoglossum radiatum (Hymenophyllaceae), and two new records with note to the genus Didymoglossum Desv. from Thailand. PhytoKeys 261: 59-75, DOI: 10.3897/phytokeys.261.157609
E277DE2D77A650158C43F9DD334C90DD.taxon	etymology	Etymology. The specific epithet – radiatum refers to the radiate and parallel arrangement of false veinlets on the fronds.	en	Chokrassameehirun, Siwakorn, Kraichak, Ekaphan, Jaruwattanaphan, Tassanai (2025): A new species, Didymoglossum radiatum (Hymenophyllaceae), and two new records with note to the genus Didymoglossum Desv. from Thailand. PhytoKeys 261: 59-75, DOI: 10.3897/phytokeys.261.157609
