Ficus flavifolia Zhen Zhang, S. Liao, Aver. & K.S. Nguyen, 2025

Zhang, Zhen, Averyanov, Leonid V., Nguyen, Khang Sinh, Bui, Van Thanh & Liao, Shuai, 2025, Ficus flavifolia (Moraceae), a new climbing fig tree from central Laos, Phytotaxa 701 (1), pp. 105-114 : 107-110

Ficus flavifolia Zhen Zhang, S. Liao, Aver. & K.S. Nguyen , sp. nov. ( Figs. 2–5 )

Type: — LAOS. Khammouane Province: Boualapha District, Nong Seng Village, the summit of Phou Chuang (Poujeuang) Mountain, around point 17°35’18.1”N 105°47’47.5”E, 1000–1400 m a.s.l., 5 May 2018, L. V. Averyanov, Khang Sinh Nguyen, T. V. Maisak, Littideth Xaiyavongsa, Siphanom Keovankham AL649a (holotype LE 01048181! https://en.herbariumle.ru/?t=occ&id=1296).

Diagnosis: —The new species is similar to Ficus howii , but strikingly distinguishable from it by its well-developed indumentum on both surfaces of leaves, petioles, branchlets, peduncles and syconia, thicker branchlets 5–6 (vs 2–4) mm in diameter, yellowish-brown abaxial surface of acrophyll (vs light green), fewer lateral veins 6–8 (vs 8–12) pairs, shorter acrophyll petioles 7–9 (vs 10–25) mm long, thicker peduncle ca. 5 (vs 2–3) mm in diameter, and ridges on the lower part of ellipsoid syconia (vs globose without ridges). These characters make the new species strikingly distinct in the F. sarmentosa complex.

Description: —Scandent or climbing shrub, gynodioecious. Branchlets thick, 5–6 mm in diameter, covered by densely brownish pubescence, sparse to glabrous in biennial branches, with pale lenticels in the biennial branches. Stipules 10–12(–14) mm long, triangular lanceolate, involute, pale green, apex acute or acuminate, outside densely brownish hairy, caducous. Leaves alternate, pseudo distichous, petiolate; petiole 7–9 mm long, ca. 3 mm in diameter, bushy brownish hairy, slightly furrowed abaxially; lamina narrowly ovate, or oblong-lanceolate, somewhat concave, (5–)7–9(–12) × (2.8–)3.5–4.5(–5) cm, symmetrical, thick, coriaceous, base broadly obtuse, rounded, or subcordate, apex acute or shortly acuminate, margin entire, adaxial surface sparsely pilose, abaxially densely yellowish-brown manicate, not foveolate, lateral veins 6–8 pairs, abaxially distinctly raised, basal veins up to 1/3 to 1/2 length of the lamina. Syconia axillary on the leafless biennial branchlets, solitary; peduncle terete, 3–5 mm long, ca. 5 mm in diameter, bushy brownish pilose; basal bracts 3, adpressed to the syconium base, broadly triangular-ovate, ca. 2.5–3.5 mm long and wide, hairy; receptacle (syconium) ovoid or ellipsoid, 1.8–2.2 × 1.5–1.8 cm, greenish, densely brownish short pilose and sparsely tuberculate, several longitudinal ridges on the lower half of syconia; ostiole ca. 2 mm in diameter, ostiole bracts greenish; internal hairs exist. Staminate flowers numerous, scattered near the ostiole, sessile to 0.5 mm long; sepals 4, light yellowish-brown to light pink, glabrous, ovate to lanceolate, up to 1 mm long; stamens 2, lanceolate, subequal to calyx in length, filament absent. Gall flowers numerous, sessile to 0.5 mm long; sepals 5–6, ovate to lanceolate, 1–1.8 mm long, glabrous; ovary subsessile, obovoid, constricted at the base, ca. 1 mm tall; style lateral, ca. 0.5 mm long; stigma shallowly funnelform. Pistillate flowers and Seed not seen.

Distribution and habitat: —The new species is currently known only from the Phou Chuang (Poujeuang) Mountain belonging to Hin Namno National Park (Khammouane Province, Laos) ( Fig. 2 ) and growing on the sandstone in primary evergreen mixed and coniferous dense wind-formed forest ( Fig. 4A ). It is locally common and should not be endangered, but the formal conservation status needs more investigation. Ficus howii also grows near the top of the Phou Chuang Mountain together with the new species ( Fig. 2 ), however, there is no data of the other sympatric fig trees.

Etymology: —The specific epithet refers to the yellowish-brown abaxial surface of lamina.

Notes: —The new species developes yellowish-brown indumentum on abaxial surface of leaf lamina ( Fig. 4C ), which is distinct from other members of the Ficus sarmentosa complex together with other traits mentioned above. The nuclear phylogenetic tree also confirms its phylogenetic position as a sister to F. howii . These evidences verify its status as a new species to science. However, in consideration of its closely phylogenetic ally F. howii which struggles in rare correctly identified specimens and color photos, leading to poor understanding of the difference between F. flavifolia and F. howii , a detailed plate of F. howii is also provided to show its characteristics ( Fig. 6 ).

Additional specimens examined: Ficus howii : — CHINA. Guangxi: Shangsi , 3 July 1933, H.D. Zeng 22623 ( IBK00088038 !) ; Ningming , 20 November 1959, X.F. Deng 10624 ( IBK00088037 !) ; Guizhou: Xingren , 28 August 1960, Guizhoudui 8712 ( NAS00292438 [image]) ; Y. Tsiang 4547 ( NAS00292436 [image]) ; Hainan: Baisha , 20 April 1936, X.Q. Liu 26366 ( IBK00088048 !) ; Yunnan: Jinghong , 2 March 1957, Zhongsudui 5453 ( NAS00292425 [image]) ; Jinghong , September 1936, C.W. Wang 78632 ( NAS00292431 [image]) ; Lincang, 3 November 1938, D.J. Yu 18165 ( PE00641828 !).— LAOS. Khammouane: Boualapha, Nong Seng , 17° 35′0.3″ N, 105° 47′35.6″E, a.s.l. ± 1000m, 4 May 2018, L. Averyana et al. AL623 ( LE01048182 !).— MYANMAR. Kachin: Putao, 13 December 2017, Y. H. Tan et al. m3495 ( HITBC!).— THAILAND. Chiangmai: Muang, 15 September 1988, J.F. Maxwell 88-1080 (L1599932[image]) ; Lampang: Wahng Nua, 25 March 1997, J.F. Maxwell 97-221 (L1615618[image]).— VIETNAM. Son La Province: Muong La District, Muong La N.R., Ngoc Chien Commune, remnants of primary evergreen broad-leaved forest on shale stone mountain, around point 21°36’32.4”N 104°06’50.3”E, a.s.l. 1200–1300 m, climbing tree up to 10 m tall, 24 July 2024, Van Thanh Bui, Thi Van Anh Nguyen, Khang Sinh Nguyen SL-ML134 ( HN!) ; Tonkin, 9 January 1931, E. Poilane 18799 (L3918522[image]). Ficus muricata : — CHINA. Yunnan: Puer, Jingdong , Qingren Valley . 20 July 2015, Z. Zhang, X.M. Wang & H.Y. Gao JDH-6 ( HSNU00075747 !), JDH-7 ( HSNU00075746 !). Yunnan: Xishuanbanna, Menghai, 30 March 1957, Sino Soviet joint Yunnan delegation 5765 ( KUN0512889 !) ; Yunnan: Xishuanbanna, Mengzhe , 2 March 1952, Sino Soviet joint Yunnan delegation 5453 ( KUN0512883 !, KUN0512884 !) ; Yunnan: Xishuanbanna, Mengla , Manhua, S.J. Pei 59-10817 ( KUN0512858 !, NAS00292427 [image]) ; Yunnan: Xishuanbanna, Mengyang, YeXiang Valley , Z. Zhang, X.M. Wang & H.Y. Gao 20150901a ( HSNU!) ; Yunnan, Honghe, Lvchun, Dingsong River , L.M. Zhou 47 ( KUN0781411 !) ; Yunnan, Honghe, Lvchun , Qimaba, H.Q. Li & Z. Zhang 2013170 ( HSNU!) ; Yunnan, Puer, Menglian, Longshan , 28 December 2009, H.Q. Li 2009435 ( HSUN00058028 !) ; Yunnan, Lincang, Cangyuan, 2 June 1974, Y.H. Li 011885 ( KUN0512861 !).— LAOS. Louang Namtha Province: Namtha District , Nalan Village , 10 November 2022, D.L. Quan, B. Yang, L. Wang, L. Seng & G. In L1287 ( HITBC!) .

Figures

FIGURE 2. The distributed points of Ficus flavifolia and its allies, F. howii and F. muricata. A. The distribution points of F. flavifolia, F. howii and F. muricata. B. type locality of F. flavifolia and the point of the sympatric fig tree F. howii.

FIGURE 3. Holotype of Ficus flavifolia (LE 01048181).

FIGURE 4. Ficus flavifolia. A. Habitat. B. Adaxial surface of lamina. C. Abaxial surface of lamina. D. Fruit branch. E. Syconium. F. Profile of staminate inflorescence. Photos from AL649a (LE).

FIGURE 5. Line drawing of Ficus flavifolia. A. Fruit branch. B. Abaxial and adaxial surfaces of acrophylls. C. Syconium. D. Profile of staminate inflorescence. E. Staminate flower. F. Stamen. G–H. Gall flowers. I. Pistil. Drawn by Mrs. Yun-Xiao Liu (IBSC).

FIGURE 6. Ficus howii. A. Plant in nature showing robust trunk. B. Vegetative branchlet. C. Fruiting branch. D. Reproduction branches. E. Dorsal view of fruit branch. F. Abaxial surface of acrophylls. G. Branchlet. H. Syconia. I. Profile of pistillate inflorescence. Photos A & C from SL-ML134 (HN); B & D–I from 20150833a and 20150886a (HSNU).