Ventilago flavovirens Cahen & Utteridge, 2017

Cahen, Daniel & Utteridge, Timothy M. A., 2017, Three new species of Ventilago (Rhamnaceae) from South-East Asia, Phytotaxa 307 (3), pp. 171-182 : 178-180

Ventilago flavovirens Cahen & Utteridge , sp. nov., ( Fig. 5 )

Ventilago flavovirens is related to V. ferruginea , but differs in its completely glabrous leaves drying yellowish green, usually shorter petioles, asymmetric leaf base and fewer pairs of more weakly elevated secondary veins.

Type:— MALAYSIA. Sabah: Ranau, Kilimu, Cultivated area , 27 August 1987, Mansus et al. SAN 122269 (holotype: K!; isotypes: E!, KEP!, SAN n.v.) .

Climber, woody, to 40 m long. Indumentum sparse at base of branchlets, dense at distal end of branchlets, very dense on inflorescence rachis, often completely hiding its surface; hairs short, cinereous to fulvous, spreading to appressed-antrorse. Branches slender, terete, smooth; branchlets often deeply ridged. Stipules fugaceous, deltoid to subulate. Leaves with lamina [narrow] ovate-elliptic to [narrow] oblong, often asymmetrical, 4.5–17.0 cm long, 2.0– 6.1 cm wide, subcoriaceous, drying yellowish green, adaxially shiny, abaxially duller, both sides glabrous and smooth but with higher order venation reticulations readily felt by touch, apex attenuate to rounded, often slightly retuse, base slightly asymmetric, obtuse-rounded to slightly cordate, margins entire, to minutely and irregularly crenate-dentate with a minute black callosity on serration tips; primary vein glabrous, abaxially ridged and conspicuously elevated; secondary veins 6–9[–11] pairs, yellowish-green when dry, often decurrent along the primary vein, glabrous, weakly to moderately elevated abaxially, unbranched and remaining separate, tertiary veins perpendicular to the primary vein, most spaced by c. 1.0 mm from each other, forming distinct horizontal lines on the adaxial lamina surface, higher order venation reticulations distinct; domatia absent; petiole 0.5–4.0 mm long, sulcate, [sub-] glabrous. Inflorescence fascicles with the leaves bearing them fugaceous so that fascicles are arranged in racemes or panicles with racemes to ca. 10 cm long, raceme rachis ca. 0.9 mm wide at base. Flowers pedicellate with a hypanthium, bisexual, 5-merous, perigynous; sepal lobes triangular, adaxially keeled with an apical protuberance; petals present, clawed, hairy abaxially, obcordate, each enclosing a stamen before anthesis; androecium apostemonous, anthers 5, dorsifixed, introrse; disk subpentagonal, filling the hypanthium, fleshy, glabrous; ovary hairy, half-immersed in disk, locules 2; style 2-fid. Fruit densely hairy, reddish-brown, with a conspicuous, globose basal portion enclosing the seed chamber and a distinct wing-like apical appendage, oblong, to 6.5 cm long and 1.2 cm wide at maturity; apex acute to rounded with style remains forming a distinct mucro; persistent calyx annular, attached at base of globose part of fruit.

Distribution:— Borneo (East Kalimantan, Sabah and Sarawak) ( Fig. 4 ).

Habitat:— Bornean rain forests; elev. 200–450 m.

Conservation status:— Near Threatened (NT). It is very likely that the taxon is declining and is severely fragmented given widespread destruction of the lowland rainforests of Borneo ( Loucks 2001a). However, the taxon is distributed with an EEO much greater than 30 000 km 2. In addition, some populations may be protected from decline as McDonald & Ismail 3530 collected within Kayan Mentarang National Park (IUCN Category II), Meijer SAN 124388 at Mount Silam within the Sepagaya Virgin Jungle Reserve (IUCN Category Ia) and Dewol S. & Lideh S. SAN 132494 perhaps within the Pin-Supu Virgin Jungle Reserve (IUCN Category Ia).

Phenology:— Collected in flower in April and June. Collected in fruit from June to September.

Etymology:— The specific epithet refers to the leaf’s yellowish green colour when dry.

Discussion:— Ventilago flavovirens is recognised by its 6–9[–11] pairs of secondary veins, weakly to moderately elevated abaxially, glabrous leaves, petiole 0.5–4.0 mm long, very dense hairs often completely hiding the inflorescence rachis surface, densely hairy fruits and persistent calyx forming a ring at the base of the fruit. Other taxa of Ventilago found in Borneo are V. borneensis , V. dichotoma , V. ferruginea and V. malaccensis . Ventilago flavovirens differs from V. borneensis in its shorter petioles, more numerous secondary veins and longer and more coriaceous fruit wings, from V. dichotoma in its subcoriaceous leaves, asymmetric leaf base, abaxially glabrous yellowish-green primary veins and hairy fruits ( Table 1) and from V. malaccensis in its shorter petioles, glabrous secondary vein axils, hairy fruits and persistent calyx forming a ring at the base of the fruit.

Additional specimens examined:— INDONESIA. North Kalimantan: Kayan-Mentarang Nature Reserve, on Bahau River at or to 3 km above confluence with Gon Biou River towards Long Alango , 2º50’N 115º50’E, 450 m, 7 July 1992, McDonald & Ismail 3530 (L!) . MALAYSIA, Sabah: Kota Kinabatangan, Simpan Pin-Supu , 400 m, 13 April 1992, Dewol S. & Lideh S. SAN 132494 ( K!, KEP!) ; Lahad Datu, Mt. Silam , 2 June 1990, Meijer SAN 124388 ( K!) ; Sarawak: Sungei Mayeng, Tau Range , 700 ft [200 m], 6 June 1956, Pursglove P. 5392 (GH!, K!, L!) .

Figures

FIGURE 4. Distribution of Ventilago ferruginea (●) and V. flavovirens (■).

FIGURE 5. Ventilago flavovirens. A habit. B detail of leaf base, abaxial view below, adaxial view above. C detail of marginal venation pattern, abaxial view. D detail of distal portion of inflorescence branch showing flower buds. E detail of flower bud. F fruiting branch. G fruit.H detail of fruit base showing indumentum. Scale bar:A, F = 3 cm; B, C, D = 4 mm; E = 1.6 mm; G = 1.5 cm; H = 3.3 mm. A–C from Dewol S. & Lideh S. SAN 132494; D, E from Purseglove 5392; F–H from Mansus et al. SAN 122269. DRAWN BY LUCY T. SMITH.