Hoya fauziana ssp. angulata Rodda, A.L.Lamb, Gokusing & S.Rahayu, 2018

Hoya fauziana ssp. angulata Rodda, A.L.Lamb, Gokusing & S.Rahayu View in CoL , subsp. nov. — Fig. 1 View Fig , 2 View Fig

Distinguished from H. fauziana ssp. fauziana by the orientation of the flowers, all facing the same direction (vs perpendicular to the pedicel axis in H. fauziana ssp. fauziana ) and by the fine pubescence of the corolla tube (vs long sericeous trichomes on the corolla tube and lobe in H. fauziana ssp. fauziana ). — Type: L. Gokusing LG56 /2017 (holo SAN), Malaysia, Sabah, Tawau, Kalabakan area, Mixed Hill Dipterocarp Forest , 16 May 2017 .

1 The Herbarium, Singapore Botanic Gardens,National Parks Board,1 Cluny

Road, 259569 Singapore;

corresponding author e-mail: rodda.michele@gmail.com. 2 P. O. Box 10960, 88810 Kota Kinabalu, Sabah, Malaysia . 3 Kipandi Park, P. O. Box 12785, 88831 Kota Kinabalu, Sabah, Malaysia . 4 Bogor Botanic Gardens, Indonesian Institute of Sciences ,Bogor, Indonesia .

Etymology. The specific epithet ‘ angulata ’ refers to the orientation of the flowers, held at an angle of 90–180° to the pedicels.

Epiphytic climber with white latex in all vegetative parts, glabrous. Stems slender, to c. 1.5 m long, internodes 10–20(–30) cm by 1.5–3 mm, brown; root adventitious sparsely produced along the stem. Leaves petiolate; petiole terete, 2–6 by 1–2 mm diam, dark green to maroon; lamina lanceolate, 8–16 by 2–5 cm, base cuneate to obtuse, apex acuminate; venation pin- nate, secondary veins hardly visible in live material, 5–12 pairs, diverging at 45–60° from the main vein, anastomosing near lamina edge, tertiary venation reticulate; dark green above with numerous grey spots, below lighter green. Colleters at lamina base 2, ovoid, 500–700 by 350–450 µm. Inflorescence positively geotropic, pseudo-umbellate, convex, 8–10(–20)-flowered; peduncle 9–10 cm long by c. 1.5 mm diam, glabrous. Pedicel 2.5–3 cm by 0.7–0.8 mm diam, reddish-maroon, very finely papillose, sharply angled just below the calyx. Calyx 3.5–4 mm diam, lobes ovate, spatulate, 1.5–2 by 0.7–1 mm wide, apex round, inside glabrous, outside very sparsely pubescent; basal colleters one in each calyx lobe sinus, ovate with a round tip, 0.23–0.35 mm long. Corolla reflexed, turban shaped, c. 13 mm diam, 18–20 mm when flattened; tube 3–4 mm long, finely pubescent inside, trichomes 130–170 µm long, glabrous outside, corolla lobes revolute, broadly ovate, 5–7 by 6–7 mm, dark orange-red, glabrous, apex acute. Corona staminal, violet red, 8–10 mm diam, 3–4 mm high; corona lobes ovoid, 4–5 by c. 2.5 mm, ridged above, below sulcate with revolute margins, outer process round raised, inner process oblong, covering anther appendages. Anthers triangular, 1 by 1 mm, with apical round membranaceous appendage exceeding the style-head apex. Pollinia oblong, 700–750 by 230–270 µm, narrowing towards the base, apex obliquely truncate, sterile edge continuous along the outer side of each pollinium; corpusculum rhomboid, 400–450 by 200–250 µm; caudicles curved, hyaline, 150–200 by 80–100 µm at the widest. Style-head 5-angled in cross sec- tion, with 5 lobes alternating with the stamens, style-head apex flat to slightly convex, c. 2 mm broad. Ovaries oblong with a round tip, 1.4–1.7 by 1–1.2 mm wide at the base, glabrous. Fruit and seed not seen.

Distribution & Ecology — Hoya fauziana ssp. angulata has been collected in one locality in Sumatra, Riau, Bukit Tiga Puluh area ( Maskuran s.n. (BO)) and in two localities in Borneo, Sabah, Malaysia, Kalabakan area ( Gokusing LG56/2017 (SAN)) and Kalimantan, Sanggau, Jangkang area ( Maskuran s.n. (BO)). In Sumatra as well as Sabah the species was collected in Mixed Hill Dipterocarp Forest, while in Kalimantan it was found in lowland mixed Dipterocarp and Heath Forest. All plants observed were epiphytic climbers.

Conservation status — Data Deficient (DD, IUCN Standards and Petitions Subcommittee 2017). Using GeoCAT ( Bachman et al. 2011) we calculated the EOO for H. fauziana ssp. angulata to be> 145 000 km 2 and the AOO> 12 000 km 2. The taxon should therefore be assessed as Least Concern. Only three populations are known and therefore it might belong to a threatened category. Only one collection is within a conservation area ( Sumatra, Bukit Tiga Puluh) while the other two localities are not within conservation areas and may in the future be converted to agriculture. However, we do not have informa- tion on the population size, number of mature individuals and habitat loss to make an accurate conservation assessment and therefore assess H. fauziana ssp. angulata as Data Deficient. Ex situ collections are present at Kipandi Park and at Bogor Botanic Garden (Acc No. BBG- B 200409390).

direction in H. fauziana ssp. angulata at angles of 90–180° to the pedicel. The species also differ in type and placement of the pubescence on the corolla: H. fauziana ssp. fauziana has sericeous hairs 250–350 µm long that are sparse on the inside of the corolla tube and dense on the inside of the corolla lobes while H. fauziana ssp. angulata has thin hairs 130–170 µm long only present on the inside of the corolla tube. Lastly the pollinium and corpusculum are larger in H. fauziana ssp. angulata (pollinium: 700–750 by 230–270 µm, corpusculum: 400–450 by 200–250 µm) compared to H. fauziana ssp. fauziana (pollinium: 650–700 by 300–350 μm, corpusculum: 350–400 by 200–220 μm).