Hylodesmum menglaense (C. Chen & X. J. Cui) H. Ohashi & R.R. Mill, Edinburgh J. Bot. 57(2): 180. 2000

Song, Zhu-Qiu, Yao, Gang, Pan, Bo, Li, Jian-Wu, Huang, Xiang-Xu, Tan, Yun-Hong & Xu, Dong-Xian, 2019, Return Verdesmum menglaense to the genus Hylodesmum (Fabaceae) based on morphological and molecular evidence, PhytoKeys 126, pp. 1-12 : 3-6

Hylodesmum menglaense (C. Chen & X. J. Cui) H. Ohashi & R.R. Mill, Edinburgh J. Bot. 57(2): 180. 2000 Figure 1

Podocarpium menglaense C. Chen & X. J. Cui, Acta Bot. Yunnan. 9(3): 305. fig. 1. 1987. ≡ Desmodium menglaense (C. Chen & X. J. Cui) H. Ohashi, J. Jap. Bot. 70(3): 142. 1995. ≡ Verdesmum menglaense (C. Chen & X. J. Cui) H. Ohashi & K. Ohashi, J. Jap. Bot. 88(3): 161. 2013, syn. nov.

Type.

China. Yunnan Province, Mengla County, Menglun Town, 21°58'N, 101°15'E, 620 m a.s.l., 6 Aug 1974, Guo-Da Tao 009050 (holotype, HITBC!, [No. 020113]; isotype, HITBC!, [No. 020112]).

Description.

Perennial herbs or subshrubs, 30-100 cm high. Stem erect, simple, usually woody at base. Stipules striate, lanceolate, 3.5 mm × 1 mm in size, green to brown, uncinate-hairy. Stipels subulate, ca. 1.4 mm long. Leaves 3-foliolate, scattered along stem; petiole 8-12 cm including rachis 1-2.5 cm long, uncinate-hairy; leaflet blades thickly papery to subleathery; adaxial surfaces dark green, shiny, glabrous; abaxial surfaces pale green, scattered with white spots, very sparsely uncinate-hairy under the microscope; terminal leaflet ovate, 12-19 cm × 7-10 cm in size, entire along margin, rounded or broadly cuneate at base, acuminate or caudate at apex, 2-stipellate at base of pulvinule; lateral veins about 5 pairs, not reaching margin; lateral leaflets slightly smaller, narrowly ovate to lanceolate, base oblique, 7-12 cm × 3-5 cm in size, sessile but pulvinule distinct, 1-stipellate at base of pulvinule; pulvinule ca. 5 mm long. Inflorescences terminal or axillary, sometimes borne at leafless nodes or near the base of old stem, pseudoracemose, up to 15-50 cm long, laxly flowered, 2-flowered per node, with minute hooked hairs. Primary bracts subtending the secondary bracts, narrowly triangular, acute at the apex, 4.3 mm × 1.6 mm in size, with uncinate hairs. Secondary bracts triangular, 1 mm × 0.7 mm in size, with uncinate hairs. Bracteole absent at base of calyx. Pedicles 2.5-3 mm long, with minute uncinate hairs. Calyx 4-lobed; tube 2.5-2.6 mm long; lobes much shorter than the tube, upper lobe minutely 2-toothed at the apex, lateral and lower lobes shallowly triangular with minute hooked hairs, 1.3-1.5 mm × 0.4-0.6 mm in size; floral disc absent. Corolla pale reddish-pink, glabrous; standard blade orbiculate or suborbiculate, 7.3 mm × 6.5 mm in size, reflexed, emarginate at the apex, suddenly cuneate to the base, with ca. 1.8 mm long claw; wings narrowly elliptic, 7.3 mm × 1.8 mm in size, slightly twisted, obtuse at the apex, slightly auriculate at the base, with ca. 1.8 mm long claw; keel-petals connate, 6.6 mm × 2.3 mm in size, obtuse at the apex, auriculate at the base, with ca. 2.3 mm long claw. Stamens 10, monadelphous, filaments connate into a tube, ca. 9 mm long. Ovary linear, minute uncinate-hairy, about 7.5 mm long including style 1.5 mm long, usually 2-5-ovuled, with a very short stipe; style curved upwards, with a terminal minute capitate stigma. Pods 2-5-jointed, linear, densely minute hooked hairy, with central isthmi between articles; fruiting pedicles 5-7 mm long, fruiting stipes 9-15 mm long; articles very narrow obovate-elliptic, 3.2-5.4 cm × 3.5-6 mm in size, covered with prominent reticulate veins when mature. Seeds 1 in each locule, very narrow obovate-elliptic, 2.5-3.5 cm × 3 mm in size, without rim-arillate around the hilum.

Distribution.

Three locations of Yunnan Province, Southwest China, were found for this species (Fig. 3 ). It usually occurs in moist conditions under the evergreen forests, with an elevation range from 600 m to 1000 m.

Phenology.

Under natural conditions in the field, the species was recorded in fruit from August to November. Under cultivated conditions in Guangzhou City, plants were observed in flower in October and in fruit from November to December.

Conservation status.

Before our investigation, only five type specimens of two fruiting gatherings have been found in a single locality for this species. We explored the type locality of this species and found two additional localities, but individual numbers of each of the three populations were discovered to be less than 30. Therefore this species might be considered as 'Critically Endangered’ (CR) under the IUCN (2001) categories criteria C2a(i).

Notes.

Hylodesmum menglaense was described as having terminal and/or axillary inflorescences in some references ( Cui et al. 1987; Gao 2006; Huang and Ohashi 2010). Through examining type specimens, however, Ohashi and Ohashi (2013) pointed out that inflorescences of this species arise from leafless nodes or from the base of old stem, but seem not to be terminal. Our observations show this species does produce terminal inflorescences as well.

Specimens examined.

CHINA. Yunnan Province: Mengla County, Menglun Town, 15 Nov 1984, 620 m a.s.l., Xian-Ju Cui & Guo-Da Tao 84111501 (KUN); Jinghong City, Jiluo Town, 995 m a.s.l., 11 Sept 2010, Zhu-Qiu Song 2010091101 (IBSC); Jinghong City, Gasa Town, 24 Dec 2017, 729 m a.s.l., Zhu-Qiu Song 2017017 (IBSC).

Figures

Figure 1. Hylodesmum menglaense (≡ Verdesmum menglaense). A habitat B adaxial leaf surface C abaxial leaf surface, showing scattered white spots D stipules E a node of inflorescences, showing a primary bract (PB) and a secondary bract (SB), but without bracteoles at base of calyx, (F) a flower with the different parts separated, especially showing the terminal minute capitate stigma of the ovary, (G) linear pods with very narrow obovate-elliptic articles, bar = 2 mm.

Figure 3. Distribution map of Hylodesmum menglaense (stars).