Licuala honbaensis Henderson & Nguyen Quoc Dung, 2017

Henderson, Andrew & Dung, Nguyen Quoc, 2017, New species of Lanonia, Licuala, and Pinanga (Arecaceae) from Vietnam, Phytotaxa 323 (2), pp. 159-172 : 164-165

Licuala honbaensis Henderson & Nguyen Quoc Dung sp. nov. ( Fig. 6 )

Type:— VIETNAM. Khanh Hoa Province: Dien Khanh District, Hon Ba Nature Reserve, 12.100N, 108.966E, 910 m, 10 July 2010, A. Henderson & Bui Van Thanh 3694 (holotype HN!, isotype NY!).

It differs from similar species with elongate ligules and ellipsoid fruits ( L. bidoupensis , L. caespitosa , and L. glaberrima ) in its calyx with the 3 apical lobes splitting again to give 6 lobes.

Stems solitary, 1.7–5.0 m tall, 5.0–8.0 cm diameter. Leaf number not recorded; sheaths length not recorded; ligules persistent, to 70.0 cm long, hanging down below the leaf bases; petioles 170.0–200.0 m long, with stout thorns to 0.7 cm long; blades split into 31–37 segments, these with straight sides; costa continuous into central segment, forming a petiolulate base to segment; middle segment 55.0–60.0 cm long, 5.0 cm wide at apex; lateral segment 50.0 cm long, 1.7 cm wide at apex; segments briefly indented at the apex, and with minute, brown scales abaxially. Inflorescences erect amongst the leaves, 160.0–200.0 cm long, branched to 2 orders; prophylls not recorded; rachis bracts tubular, 10.0 cm long, fraying at the apices; partial inflorescences 6–9 partial; rachillae 17.0–24.0 cm long, densely covered with short, brown, felty hairs; flowers 3.0– 3.5 mm long, 2–3 borne together on a scarcely raised pedicel, the clusters distantly spaced along the rachillae; calyx 2 mm long, hairy as the rachillae, the base not tubular, the 3 apical lobes splitting again to give 6 lobes; corolla 3.0 mm long, with minute, appressed hairs distally, splitting about half way into 3, valvate petals; stamens 6; staminal ring 0.5 mm long; filaments free for ca. 0.5 mm; anthers oblong; pistil 2 mm long; fruits immature, ellipsoid.

Distribution and habitat:—Southern Vietnam in Khanh Hoa province in lowland rainforest on steep slopes at 500–910 m elevation.

Taxonomic notes:— Licuala honbaensis appears similar to a group of species having leaf segments not joined at the apices; tubular rachis bracts; long rachillae with scarcely raised, distantly spaced pedicels; small, somewhat rounded flower buds; and ellipsoid fruits. This group comprises L. bidoupensis , L. caespitosa , and L. glaberrima . It differs from these in its calyces splitting into 6 lobes, a character state previously known only in Lanonia .

Additional specimens examined. VIETNAM. Khanh Hoa province: Hon Ba Nature Reserve , road to summit, undisturbed forest on steep slopes, 12.11N, 108.98E, ca. 500 m, 4 July 2014, Henderson & Nguyen Quoc Dung 3893 ( NY, VFM) ; same locality, same date, Henderson & Nguyen Quoc Dung 3895 ( NY, VFM) .

Figures

FIGURE 6. Licuala honbaensis. Left, habit. Right, rachilla with immature, ellipsoid fruits (from Henderson & Bui Van Thanh 3694).