Urophyllum brochidodromum Yooprasert, Culham & Utteridge, 2022

Yooprasert, Sawita, Culham, Alastair, Tagane, Shuichiro, Yahara, Tetsukazu, Nguyen, Van Du, Nguyen, Khang Sinh & Utteridge, Timothy M. A., 2022, New species and new status of Urophyllum Wall. (Rubiaceae) from Cambodia and Viêtnam, Adansonia (3) 44 (11), pp. 91-114 : 101-104

Urophyllum brochidodromum Yooprasert, Culham & Utteridge , sp. nov.

( Figs 7 ; 8 )

Urophyllum brochidodromum Yooprasert, Culham & Utteridge , sp. nov. is similar toU. lecomtei Pit. but differs in the secondary veins strongly joining together to form closed loops close to the leaf margin with no additional sets of loops (conspicuously brochidodromous), while in U. lecomtei , the veins are joined with a series of small loops (festooned brochidodromous). The species also differs in its calyx lobes, which are recurved, at least at the fruiting stage compared to the erect to incurved lobes found in U. lecomtei .

TYPE. — Viêtnam. Kon Tum Province, Dak Gley [Dak Glei District], about 12 km to N of Dak Gley town (24 km by road), near Mang Khen Village , 1100-1200 m elev., 14.XI.1995, Averyanov et al. VH 1648 (♀) (holo-, AAU!) .

ADDITIONAL SPECIMENS EXAMINED . — Viêtnam. Bin Tri Thien [Quang Binh, Quang Tri and Thua Thien Hue Provinces], 9.VIII.1980, Hoang 67 (♀) ( HN!). — Kon Tum Province, Ngoc Linh Nature Reserve, 15°12’24.2”N, 107°46’10.4”E, 1365 m elev., 14.II.2017, Tagane et al. V 6648 (♀) ( DLU n.v.; FU!). — Quang Binh Province, Bo Trach District, Hung Trach municipality, Phong Nha-Ke Bang NP, between km 51 and 56 of west branch of Ho Chi Minh Road., 17°27’30”N, 106°23’6”E, c. 650 m elev., 4.VII.2004, Wu et al. WP 928 (♀) ( HN!). — Thua Thien Hue Province, A Luoi District, 25.V.2005, Binh & Cuong VN 1506 (♂) ( HN!) .

ETYMOLOGY. — The specific epithet refers to the conspicuously brochidodromous lateral veins.

DISTRIBUTION. — Viêtnam: Kon Tum Province (Ngoc Linh Nature Reserve), Quang Binh Province (Phong Nha-Ke Bang National Park) and Thua Thien Hue Province (A Luoi District) ( Fig. 3 ).

HABITAT. — Evergreen forest to evergreen montane forest, by streams; elev. 650-1400 m.

PHENOLOGY. — Flowers collected in May and fruits from August to February.

CONSERVATION STATUS. —Vulnerable (VU) B1ab(iii)+2ab(iii)+D2. The species has an estimated EOO of 2470 km 2 and AOO of 16 km 2 both below the Endangered (EN) threshold, and is only known from three locations; however, two locations are within the protected areas of Ngoc Linh Nature Reserve (IUCN category IV) and Phong Nha-Ke Bang National Park (IUCN category II) where the risk of deforestation is unlikely to increase dramatically. One specimen was collected in A Luoi District which is not a protected area, with concerns for the expansion of agriculture land use growing Acacia species and Cassava in the future ( Pham 2019). Therefore, the species is rated as Vulnerable. However, there is Phong Dien Nature Reserve (IUCN category IV) which has continuous forest to the northeast of A Luoi District viewing on the Google Earth in 2021. If further collections reveal the presence of the species in this area, the rating could be reviewed as Near Threatened.

DESCRIPTION

Shrub or treelet to 2 m high. Indumentum of appressed to erect hairs, 0.5-1.5 mm long, scattered on old stems, dense on other parts except adaxial leaf lamina. Branches terete; young shoots flattened, ridged. Stipules caducous usually left only at shoot, lanceolate 1.1-1.4 cm long, 0.15-0.33 cm wide, appressed to the stem but not folded, abaxially densely hairy. Leaves chartaceous, elliptic to oblong, 13.0- 15.1 cm long, 3.9-4.8 cm wide, apex attenuate to acuminate, base cuneate; adaxially glabrous, abaxially densely hairy, drying dull dark yellowish green adaxially, lighter abaxially with yellowish brown veins, adaxially midrib hairy; secondary veins 13-17 pairs, adaxially densely hairy, conspicuously brochidodromous, usually without additional sets of small loops; tertiary veins alternate percurrent, angle increasing exmedially, obtuse to midrib; petioles 1.0- 1.5 cm long, canaliculate. Inflorescence axillary, pedunculated umbellate, peduncle 2.2-2.9 mm long, bracts lanceolate, 3-4 mm long, only fruit bearing pistillate plant known. Fruits baccate, subglobose, c. 3 mm diam. in sicco; petiole c. 5 mm; calyx fused, lobes 5, persistent, 1-2 mm long, recurved. Seed numerous, subelliptic, surface alveolate, orange brown in sicco.

REMARKS

Urophyllum brochidodromum Yooprasert, Culham & Utteridge , sp. nov. is recognised by having strongly brochidodromous and dense hairs on both adaxial midrib and secondary venation. The persistent recurved calyx is an additional diagnostic character. The species is similar to U. lecomtei in its erect dense hairs over all parts but differs by the characters previously stated in the diagnosis: U. lecomtei has hairs only on the adaxial midrib, secondary veins festooned brochidodromous (main loops with sets of smaller loops) and calyx erect or sometimes curved toward adaxial side in fruit. There are records of U. argenteum Pit. found in Bach Ma National Park, Thua Thien Hue Province. This national park is further south c. 70 km away from A Luoi District where one population of U. brochidodromum Yooprasert, Culham & Utteridge , sp. nov. was found. Urophyllum argenteum is distinguished from U. brochidodromum Yooprasert, Culham & Utteridge , sp. nov. by its coriaceous leaves, adaxial leaf side shiny and glabrous, secondary veins eucamptodromous to weakly brochidodromous with inconspicuous loops and erect calyx lobes.

Figures

FIG. 7. — Urophyllum brochidodromum Yooprasert, Culham & Utteridge, sp. nov., illustration of pistillate plant: A, fruiting branch; B, stipule and abaxial petiole; C, adaxial petiole; D, young stem; E, infructescence; F, fruit; G, seed; H, leaf lamina, adaxial side showing midrib and secondary veins (H1) and abaxial side showing midrib and veins (H2). Drawn by Mahsarahka Rungkrajang.Drawn from Averyanov et al. VH 1648. Scale bars: A, 1 cm; B, C, 2 mm; D, F, 1 mm; E, 3 mm; G, 0.5 mm; H1, 1.5 mm; H2, 5 mm.

FIG. 8. — Holotype of Urophyllum brochidodromum Yooprasert, Culham & Utteridge, sp. nov.

FIG. 3. — Occurrences of Urophyllum annamense (Pierre ex Pit.) Yooprasert, Culham & Utteridge, stat. nov. (), U. brochidodromum Yooprasert, Culham & Utteridge, sp. nov. (), U. pulchristipulum Yooprasert, Culham & Utteridge, sp. nov. () and U. pseudoschmidtii Yooprasert, Culham, Yahara, Tagane & Utteridge, sp. nov. ().