Crepidium bahanense (Hand.-Mazz.) S.C.Chen & J.J.Wood, Fl.

Abstract, Kumar P. & Kong, Hong, 2023, Orchid Flora of Hong Kong: the addition of Crepidium bahanense, Rheedea 33 (3), pp. 199-203 : 199-202

Crepidium bahanense (Hand.-Mazz.) S.C.Chen & J.J.Wood, Fl. China25:232. 2009. Malaxis bahanensis (Hand.-Mazz.) Tang & F.T.Wang, Acta Phytotax. Sin. 1: 71. 1951. Microstylis bahanensis Hand.-Mazz., Symb. Sin. 7: 1350, t. 42, 6–7. 1936. Type: CHINA, Yunnan, Bahan (Pehalo), in the grasses near Salween River, 21.07.1916, Handel-Mazzetti 9574 (holo WU [WU0061601!]). Fig. 1

Terrestrial leafy herbs, 8–13 cm tall, with homoblastic corms placed on ground or partly covered in debris. Corms globose to sub-globose, 0.9–1 cm in diam., multi-noded, vermiform tufted roots emerging from the lower part, upper part bearing leaves. Leaves 2, coriaceous, green; lamina ovate to oblong-lanceolate, 3–3.5 × 1–1.3 cm, obtuse to acute at apex, slightly undulate at margin, dark green above, pale green below, 3-veined, veins prominently dark green underneath; petiole amplexicaule, 1.8–2 × 0.02–0.03 cm. Inflorescence erect, emerging from the apex of the corm in the middle of two leaves, 8–9 cm tall, keeps growing till the last flower opens, strongly ridged, green with reddish-brown markings, lower part with up to 8 sterile bracts, upper part with up to 18 flowers. Floral bracts triangular, 0.3–0.4 × c. 0.01 cm wide, acuminate at apex, strongly reflexed downwards. Pedicel-with-ovary clavate, 0.15–0.2 cm long, strongly ribbed, green. Flowers fully open, nonresupinate, laxly placed, 0.3–0.4 cm long, slightly shorter in width; sepals, petals and labellum yellowish green with reddish brown markings towards the apices. Dorsal sepal ovate, up to 2 mm long, c. 1.5 mm wide, acute at apex, margin strongly reflexed backwards; lateral sepals slightly shorter and broader, margin slightly reflexed backwards. Petals linear, c. 2 × 0.2 mm, acute at apex, margin slightly reflexed backwards. Labellum oblong, c. 4 mm long, 3-lobed with distinct notches distinguish mid-lobe and side lobes; side lobes falcate, c. 1.5 mm long, acute at apex, bend downwards, arching under the column with apices of both lobes parallel on either side of the column in fresh flowers, overlapping each other towards the apex in mature flower; mid-lobe erect, 2–2.5 × c. 2.5 mm, proximally bilobulate, with a prominent grove at the top, lobes quadrangular in outline, truncate at apices, central disc above the column raised with orbicular rim and an ovate cavity above the column base. Column short, stout, c. 1 × 0.5 mm, with stelids projecting forwards from either side of the stigmatic cavity; stelidia linear, c. 0.5 mm long, apex retuse; clinandrium round; pollinia 4 in 2 pairs, each pair clavate, unequally lobed; anthercap trapezoid, not covering the whole pollinia. Fruits not seen.

Flowering & fruiting: Plants were seen in flower in mid-June in Hong Kong, but in Yunnan, where the type specimen was collected, and in Loei ( Thailand), plants flowered in June and July ; fruiting not seen .

Habitat: In Yunnan, this species was found growing among Pteridium Gled. ex Scop. (Dennsteadtiaceae) in grasslands on shale rocks in a hot temperate area at an elevation of around 2,600 m ( Chen & Wood, 2009). In Hong Kong, two individual plants were found growing together on exposed, shortheighted grasslands at an elevation of around 400 m. In Thailand, the plants were found growing in sandy soil along streams and shallow, moist depressions in open grassland at an elevation of around 1,200 m ( Nuammee et al., 2016) .

Specimens examined: Crepidium allanii : CHINA, Hong Kong, Hong Kong Island, Repulse Bay , 25.03.1975, S. Y . Hu 13551 (holo, CUHK!; iso, K [ K00094281 !]); 1983, OM 9 ( KFBG [ KFBG14345 !]); 15.03.2019, Pankaj Kumar KFBG 4611 ( KFBG [ KFBG14484 !]) ; Hong Kong Island, Tai Tam catchment, 19.06.1999, Y. S .Lau 2993 ( HK [ HK 33337!]). Crepidium bahanense : CHINA, Hong Kong, New Territories , open hilltop grasslands, 400 m, 20.06.2023, Pankaj Kumar 12329 (HK!-only photographs). Crepidium purpureum : CHINA, Hong Kong, New Territories , Tai Mo Shan, 18.07.2013, Pankaj Kumar 12243 ( KFBG!); New Territories, Tai Mo Shan, 08.11.1972, S. Y . Hu 12449( A) ( CUHK); Ibid., 01.06.1969, Y. S . Lau 1494 ( HK); New Territories, Hills of Tai Po Kau, 08.11.1972, S. Y . Hu 12451 ( K!-yellow form); New Territories, Tai Mo Shan, North slope, 09.06.966, G . Barretto 2 ( K) . INDIA, Khasi Hills , Lobb s.n. ( K!) . NEPAL, Ganesh Himal, Sathigaon, 1919, Jordan & Lachard 847263 ( K!) .

Conservation assessment: Crepidium bahanense was originally recorded from Yunnan in 1936 ( Handel-Mazzetti, 1936) and later reported from Thailand ( Nuammee et al., 2016). Hence, its occurrence in Hong Kong was unexpected, as the new site in Hong Kong is about 1400 km away from the other two sites and is located at a much lower elevation. Only two plants were seen to occur at a single site, and multiple attempts to find more individuals went in vain. However, owing to the green-coloured leaves, it is highly probable that the plants were hiding among the green grasses. Also, there is a high chance of occurrence of more individuals of this species in Hong Kong and adjoining areas. As it is a recently discovered species, more surveys and studies would be needed to do a regional assessment, hence the species is assessed here regionally as Data Deficient. At global scale, the Area of Occurrence (AOO) and Extent of Occurrence (EOO) is estimated using GeoCAT (Bachman & Moat, 2012) as 12 km 2 and 784,791 km 2 respectively. In Hong Kong, hikers, local enthusiasts and poachers go looking out for orchids and while doing so some of them not only disturb the habitat but also collect orchids for horticultural use. This species grows in grassland habitats with a threat of hill fire. Owing to such disturbances, the three sites in China ( Yunnan and Hong Kong) and Thailand are treated as three locations following IUCN guidelines (IUCN Standards and Petitions Committee, 2022). The total number of mature plants in Hong Kong so far is two, however, the population size is not known at the other two sites. Based on available information, this species can be assessed on the global level as Endangered [EN B2a(iii)] following IUCN guidelines (IUCN Standards and Petitions Committee, 2022).

Notes: Crepidium bahanense can be easily distinguished from the other two members of this genus native to Hong Kong: C. allanii (S.Y.Hu & Barretto) Kumar & S.W.Gale and C. purpureum (Lindl.) Szlach. In comparison, C. bahanense has smaller (≤ 5 cm long, in comparison to more than 7 cm long in the other two) non-plicate leaves (plicate in other two) and labellum mid-lobe lobules with truncate apices (lobule rounded in C. allanii and ovate in C. purpureum ) (please also see Fig. 2 and Table 1). While, the fourth native Hong Kong member Crepidium cordilabium T.P.Lin is very distinct from the rest in size and morphology owing to it’s unnotched mid-lobe.

Figures

Fig. 1. Crepidium bahanense (Hand.-Mazz.) S.C.Chen & J.J.Wood.: a. Close up of leaves; b. Plant in habitat; c. Close up of inflorescence; d. Close up of buds;e–g. Front and side views of fully open flowers (from Pankaj Kumar 12329; photos by Pilcher Ngai).

Fig. 2. Comparison of three species of Crepidium found in Hong Kong.: a. Crepidium allanii (S.Y.Hu & Barretto) Kumar & S.W.Gale; b. C. bahanense (Hand.-Mazz.) S.C.Chen & J.J.Wood; c. C. purpureum (Lindl.) Szlach.; d. C. cordilabium T.P.Lin (photos a, c & d by Pankaj Kumar,b by Pilcher Ngai).