Dolichos kongkandae Meeboonya, Ngerns. & Balslev, 2021

Meeboonya, Rumrada, Ngernsaengsaruay, Chatchai & Balslev, Henrik, 2021, Dolichos kongkandae sp. nov. and lectotypification of D. fragrans (Leguminosae, Papilionoideae) from Asia, PhytoKeys 175, pp. 55-65 : 55

Dolichos kongkandae Meeboonya, Ngerns. & Balslev sp. nov. Figs 1 , 2

Diagnosis.

Dolichos kongkandae is most similar to D. tenuicaulis , but differs in having a densely-pubescent stem (versus slightly pubescent), ovate or broadly elliptic stipules (versus lanceolate, elliptic or subtriangular), a longer axis of inflorescence, 1-3 cm long (versus 0.3-0.5 cm long), the corolla dark purple turning blackish-purple when dried (versus purplish-pink or pale pink turning pale yellow when dried), a larger standard, ca. 12 × ca. 14 mm (versus 8-9 × 8.5-9 mm), wing petals, ca. 16 × ca. 8 mm (versus 10-11 × 3-4 mm), keel petals 11-12 × 3-4 mm (versus 9-10 × 2-2.5 mm) and a hirsute fruit stalk (versus slightly puberulous).

Type.

Thailand. Chiang Mai, Chiang Dao, Doi Chiang Dao Wildlife Sanctuary, near the beginning of Khun Huai Mae Kok Ranger Station (Den Ya Khat) nature trail, 24 Nov 2017, R. Meeboonya & P. Yodboplub 406 (holotype BKF!; isotypes AAU!, BK!).

Description.

Perennial herb, stem slender, twining, densely pubescent. Stipules persistent, ovate or broadly elliptic, 3-5 × 1.5-3 mm, with striate veins, apex acute, base subcordate or truncate, abaxial surface pubescent, adaxial surface glabrous. Leaves trifoliolate pinnately compound, alternate, petiole 2.5-7 cm long, sparsely pubescent; rachis 0.8-1.8 cm long, sparsely pubescent. Leaflets densely pubescent on both surfaces, with 4-6 lateral veins on each side; terminal leaflet ovate, lanceolate or broadly ovate, 3.5-8 × 1.5-4.5 cm, apex acute and apiculate, base rounded, obtuse or subcordate, margin entire; lateral leaflets slightly obliquely ovate or obliquely lanceolate, 3.5-7 × 1.2-3.5 cm, apex acute and apiculate, base rounded, obtuse or subcordate, margin entire; stipels persistent, attached to the base of petiolules of leaflets, elliptic, lanceolate or obovate, 2-2.8 × 1-1.2 mm, with striate veins, apex acute, base truncate, abaxial surface hirsute, adaxial surface glabrous; petiolule 1.5-3 mm long, densely pubescent. Inflorescences axillary, with 2-10 fascicles arranged in nodose-pseudoracemes or nodose-pseudopanicles; peduncle 2-5 mm long, sparsely hirsute; axis 1-3 cm long, hirsute; bracts of fascicle 2, persistent, lanceolate, 2-2.5 × 0.5-1 mm, with striate veins, apex acute, base obtuse, margin ciliate, abaxial surface pubescent, adaxial surface glabrous. Flowers 1 in each fascicle; pedicel 2-3 mm long, densely hirsute; bracteoles 2, attached near the apex of pedicel, ovate, 1.8-2 × 0.8-1 mm, apex acute or acuminate, base obtuse, margin ciliate, abaxial surface pubescent, adaxial surface glabrous. Calyx greenish-purple, campanulate, 5-lobed, calyx tube ca. 4.5 × ca. 5.5 mm, 2 upper lobes connate, apex slightly divided to shallow lobes, the lowest of 3 lower lobes deltoid, ca. 2 × ca. 2.5 mm, apex acute, 2 lateral lobes deltoid, ca. 1 × ca. 1.5 mm, apex acute, abaxial surface sparsely pubescent, adaxial surface glabrous. Corolla pentamerous, dark purple, turning blackish-purple when dried, with clawed petals; standard petal, suborbicular, ca. 12 × ca. 14 mm, apex emarginate, near the centre with 2 appendages on adaxial surface, 1.5-2 mm long, base with 2 small auricles, ca. 1 mm long, the claw white, 1-2 mm long; wing petals, obovate, ca. 16 × ca. 8 mm, apex emarginate, base with 1 appendage, 1.5-2 mm long, the claw white, ca. 4 mm long; keel petals oblong, 11-12 × 3-4 mm, pubescent along the inner margins, apex truncate, the claw white, ca. 4 mm long. Stamens 10, diadelphous, 9 filaments connate and a vexillary filament free, filaments white, ca. 10 mm long; anthers uniform and dorsifixed, yellow, oblong, ca. 0.5 mm long. Pistil simple, ovary superior, ca. 9 mm long; ovary light green, linear, pubescent, base shortly stipitate; style flattened; stigma capitate with long hairs. Fruits oblong, slightly falcate, 5-7.5 cm × 6-8 mm, glabrous or slightly pubescent along both margins, apical beak 3-5 mm long, base stipitate, 2-3 mm long; fruit stalk 3-5 mm long, hirsute. Seeds 5-8, young seeds light green, dry seeds brown, elliptic or oblong, compressed, ca. 4 × 2.5-3 mm.

Phenology.

Flowering and fruiting from August to December.

Distribution.

Bhutan, India, Myanmar, China, Laos, Thailand.

Ecology.

Open areas in montane rain forests, mixed deciduous forests, limestone ridges, 550-2150 m alt.

Vernacular name.

Thua doi dok muang kongkanda (ถั่วดอยดอกม่วงก่องกานดา), the name is here given by the authors. This vernacular name references legumes (thua), the hills or mountain regions of its origin (doi), purple corolla (dok muang), and our mentor (Dr. Kongkanda Chayamarit).

Conservation status.

Dolichos kongkandae is widely distributed in its habitats. However, these areas are disturbed by the human activities. It is therefore considered as Near Threatened ( NT), following the IUCN Red List Criteria and Categories version 14 ( IUCN 2019).

Etymology.

The specific epithet is named in honour of Dr. Kongkanda Chayamarit, the expert botanist of the Forest Herbarium and the Flora of Thailand Project. She was the former supervisor of Associate Professor Dr. Chatchai Ngernsaengsaruay in his master’s and doctoral degrees and the thesis co-advisor of Dr. Rumrada Meeboonya in her master’s and doctoral degrees. She has always encouraged and supported us.

Additional specimens examined.

Bhutan. Kauchaw, Punakha, 21 Aug 1914, R. E . Cooper & A . K . Bulley 3279 ( BM!, E!); 26 Aug 1915, R. E . Cooper & A . K . Bulley 4627 ( BM!, E!) . India. Assam, Karong , Manipur, 26 Sept 1950, W. N . Koelz 26277 ( L!); 9 Oct 1869, C. B . Clarke s.n. ( K!); 3 Oct 1875, C. B . Clarke 24925 ( BM!, K!) . Myanmar. Mandalay, Maymyo plateau, 3 Oct 1908, J. H . Lace 4270 ( E!, K!) . China. Yunnan, Aug 1912, G. Forrest 8821 ( E!); ibid., Aug 1913, G. Forrest 11966 ( E!) . Thailand. Chiang Mai: Doi Chiang Dao, 2 Nov 1922, A. F . G. Kerr 6514 ( BK!, BM!, E, K); ibid., 14 Oct 1926, Put 322 ( AAU!, BK!, BM!, E!, K!); ibid., 9 Nov 1962, T. Smitinand, M. E . D. Poore & R . G . Robbins 7742 ( BKF!); ibid., 25 Sept 1971, G. Murata, K. Iwatsuki & C . Phengklai T-14920 ( BKF!); ibid., 25 Sept 1971, G. Murata, K. Iwatsuki & C . Phengklai T-14930 ( AAU!, BKF!, L!); ibid., 25 Sept 1971, J. E . Vidal 5161 ( AAU!, P!); ibid., 27 Sept 1971, J. E . Vidal 5233 ( AAU!, P!); ibid, 27 Oct 1979, T. Shimizu, H. Toyokuni, H. Koyama, T. Yahara, T. Santisuk & C . Niyomdham T-21180 ( BKF!); ibid., 4 Nov 1995, J. F . Maxwell 95-1051 ( BKF!, CMUB!, L!); ibid., Dec 2000, T. Rotjanadirok 81 ( CMUB!); ibid., 12 Nov 2011, R. P . Clark, P. Wilkin, P. Suksathan, A. Trias-Blasi & Phitak 211 ( K!); ibid., 12 Nov 2011, R. P . Clark, P. Wilkin, P. Suksathan, A. Trias-Blasi & Phitak 230 ( K!); ibid., 11 Nov 2012, V. Chamchumroon, M. Callmander, S. Christoph, C. Davidson, J. Regalado, S. Sirimongkol, N. Ritphet & S . Lai-lung 5564 ( BKF!); ibid., 7 Nov 2013, A. N . Egan, R. P . Clark, S. Sirimongkol, V. Chamchumroon & R . Meeboonya 13-0806 ( K!); Mae Taeng , 30 Oct 1922, A. F . G. Kerr 6491 ( BK!, BM!, C!, K!) .

Notes.

Dolichos kongkandae has been usually confused with D. tenuicaulis (Fig. 3 ) because of some morphological similarities. This is especially true of dried herbarium specimens.

The type specimens of Phaseolus tenuicaulis Baker (the basionym of D. tenuicaulis ), Wallich Cat. no. 5598 D (holotype K 001121419!), has a slightly pubescent stem, lanceolate, elliptic or subtriangular stipules, shorter axis of the inflorescence and the corolla turning pale yellow when dried. It also has a smaller standard, wing and keel petals and a slightly puberulous fruit stalk all of which distinguish it from D. kongkandae (Table 1 ).

Craib (1912) published D. tenuicaulis , based on the specimens of Lace 4270 and Robertson 14. Moreover, he cited D. falcatus , based on the specimens of Housseus 45 and Kerr 834. We studied these specimens and found that Housseus 45, Kerr 834 and Robertson 14 are similar to D. tenuicaulis . However, the specimens of Lace 4270 have a densely-pubescent stem and leaves, ovate or broadly-elliptic stipules, longer axis of the inflorescence, densely-hirsute pedicel and the corolla turns to blackish-purple when dried; it has a larger standard, wing and keel petals and a hirsute fruit stalk which is not similar to D. tenuicaulis and these specimens are similar to D. kongkandae .

Craib (1928) reported D. tenuicaulis as occurring in Thailand, based on the specimens Hosseus 45, Kerr 834, Kerr 4569, Kerr 6491, Kerr 6514, Put 322 and Winit 1542. We studied these specimens and found they can be separated into two groups. The specimens Kerr 834 from Doi Suthep, Chiang Mai Province, Hosseus 45 and Kerr 4569 from Nakhon Sawan Province and Winit 1542 from Lamphun Province have slightly pubescent stem and leaves, lanceolate, elliptic or subtriangular stipules, shorter axis of inflorescence, puberulous pedicel, the corolla turning to yellow when dried, has smaller standard, wing and keel petals and slightly puberulous fruit stalk, similar to D. tenuicaulis , whereas Kerr 6491, Kerr 6514 and Put 322 from Chiang Mai Province are D. kongkandae .

We thoroughly examined the specimens of Dolichos from Thai and foreign herbaria. We consistently found that the herbarium specimens of D. kongkandae were misidentified as D. tenuicaulis . Dolichos kongkandae is distributed in Bhutan, India, Myanmar, Laos and Thailand. In Thailand, it is only found in Doi Chiang Dao and Mae Taeng, Chiang Mai Province. Dolichos tenuicaulis is distributed only in Myanmar and the northern, north-eastern and south-western regions of Thailand (Fig. 5 ).

Figures

Figure 1. Dolichos kongkandae R. Meeboonya, Ngerns. & Balslev A stem with leaves, inflorescence and infructescences B calyx C inflorescence with a flower D standard petal E wing petals F keel petals G bracts of fascicle H bracteoles I pistil J stamens K seed. Drawn from R. Meeboonya & P. Yodboplub 406 (BKF) by Rumrada Meeboonya.

Figure 2. Dolichos kongkandae R. Meeboonya, Ngerns. & Balslev A habit B leaf C inflorescence with flower buds D inflorescence with young and mature flowers E inflorescence with a mature flower and a young fruit F infructescence with a mature fruit. Photographs from R. Meeboonya & P. Yodboplub 406 (BKF).

Figure 3. Dolichos tenuicaulis (Baker) Craib A leaf B, C inflorescence with a mature flower. Photographs from R. Meeboonya, K. Kommongkol, T. Napiroon, P. Wessapak & P. Yodboplub 372 (BKF).

Figure 5. The geographical distribution of Dolichos kongkandae R. Meeboonya, Ngerns. & Balslev, sp. nov. and D. tenuicaulis (Baker) Craib.