Aristolochia yangii X.X.Zhu & J.S.Ma, 2019

Zhu, Xinxin, Li, Xiaoqin, Liao, Shuai, Li, Guodong & Ma, Jinshuang, 2019, The taxonomic revision of Asian Aristolochia (Aristolochiaceae) V: two new species from Yunnan, China, PhytoKeys 130, pp. 93-106 : 95-98

Aristolochia yangii X.X.Zhu & J.S.Ma sp. nov. Figures 4 , 5 , 6 , 7 J–L

Type.

CHINA. Yunnan: Baoshan, Longyang District, Hundred Flowers Ridge, 98°47.38'E, 25°18.00'N, 1890 m a.s.l., 13 May 2018, X.X.Zhu ZXX18073 (holotype: CSH [CSH-0153654!]; isotypes: CSH!, KUN!).

Diagnosis.

Similar to Aristolochia cucurbitoides C.F.Liang ( Liang 1975) and A. forrestiana J.S.Ma ( Ma 1989b), but differs from the former in its flower larger, basal tuber 2.5-3.5 cm long; limb 3.3-4.7 cm long; deeply 3-lobed, lobes ovate-deltoid, 1.6-2.4 cm long (vs. flower smaller, basal tuber ca. 2 cm long; limb ca. 2 cm long; shallowly 3-lobed, lobes lanceolate-acuminate, 0.5-0.7 cm long in A. cucurbitoides ) and differs from the latter in its lamina lanceolate to hastate, 8-24.5 × 1.2-5.5 cm, base auriculate to cordate (vs. lamina ovate to narrowly ovate, 7-21 × 3-10.5 cm, base cordate in A. forrestiana ), calyx yellowish-white (vs. light brown or purple in A. forrestiana ), as well as limb symmetric, 3.3-4.7 cm long, straight extended from upper tube and parallel to it; deeply 3-lobed, lobes ovate-deltoid; inside pinkish or ochre without processes (vs. asymmetric, 6-8 cm long, forming right angle with upper tuber; 3-lobed, lobes lanceolate; inside black purple with dense processes in A. forrestiana ). Detailed morphological comparisons amongst the three species are summarised in Table 2 and comparisons between A. pseudoutriformis and A. forrestiana are also shown in Fig. 7 .

Description.

Semi-deciduous climbing shrubs. Stems terete. Petioles 1-4 cm long, densely pubescence; laminas lanceolate to hastate, 8-24.5 × 1.2-5.5 cm, adaxially glabrous or sparsely pubescence along medial vein, abaxially densely pubescence, base auriculate to cordate, margin entire, apex acute; veins palmate, 2-3 pairs from base, lateral veins 6-15-paired. Cymes on old woody stems or axillary, 1-2-flowered, in clusters of 1 to numerous; pedicels 5-7 cm long, sparsely pubescence; bractlets 1 or 2, ovate-lanceolate, 3-5 mm long, adaxially glabrous, abaxially densely brown villous. Calyx tube geniculately curved, yellowish-white with distinct purple stripe, abaxially subglabrous or sparsely villous; basal tuber 2.5-3.5 cm long, inside black purple at base, white mix with more or less reddish-violet above base, upper tube 2.5-3.5 cm long, inside white mix with reddish-violet, limb cylindric, symmetric, 3.3-4.7 cm long, straight extended from upper tube and parallel to it, inside pinkish or ochre, deeply 3-lobed, lobes ovate-deltoid, 1.6-2.4 cm long; throat ca. 7 mm in diam. Anthers 6, oblong, ca. 2 mm long, adnate in 3 pairs to base of gynostemium, opposite to lobes. Gynostemium ca. 3.5 mm long, 3-lobed. Ovary terete, 15-25 mm long, densely brown villous. Fruit stem purple red, ca. 6.5 cm long, sparsely puberulous. Capsule narrowly obovate-elliptic, distinctly 6-angled, nearly glabrous, ca. 10.5 × 2.5 cm (ca. 8.5 × 2 cm in dry specimens). Seeds ovate-elliptic, 5-5.5 × 3.5-4 mm, not winged, the adaxial surface deeply concave and the abaxial surface convex, wrinkled, both surfaces glabrous.

Phenology.

Flowering May and fruiting from July to August.

Etymology.

The new species is named after Zhiguang Yang, who first discovered this rare species and who accompanied us on a number of subsequent field expeditions in Hundred Flowers Ridge, Baoshan, Yunnan. The Chinese name is given as “杨氏马兜铃”.

Distribution and habitat.

The new species is currently known to Longyang District, Baoshan, Yunnan, China. It grows in forests at an elevation of between 1880 m and 2130 m, together with Castanopsis ssp. ( Fagaceae ), Disporum sp. ( Colchicaceae ), Elytranthe albida (Bl.) Bl. ( Loranthaceae ), Nervilia tahanshanensis T.P.Lin & W.M.Lin ( Orchidaceae ), Rubus sp. ( Rosaceae ), etc.

IUCN Red List Category.

Aristolochia yangii is known from only three populations, with fewer than ten individuals seen at each site. Therefore, the new species is assigned a preliminary status of Vulnerable (VU D2) according to IUCN Red List Criteria ( IUCN 2012), indicating a population with a very restricted area of occupancy (typically less than 20 km2) or number of locations (typically five or fewer).

Specimens Examined.

CHINA. Yunnan: Longyang District, 30 Mar 2015, X.X.Zhu & Z.X.Hua ZH028 (CSH); 4 June2017, X.X.Zhu ZXX17074 (CSH); 11 Aug 2018, X.X.Zhu & J.Wang ZXX18242 (CSH).

Figures

Figure 4. Aristolochia yangii X. X. Zhu & J. S. Ma, sp. nov. A habit B inflorescence C opened flower (showing the inside structure) D anthers and gynostemium E fruit. Illustration by Manhua Lin (A - D); Illustration by Shizhen Qiao (E).

Figure 5. Aristolochia yangii X. X. Zhu & J. S. Ma, sp. nov. A habit B leaves C inflorescence D flower bud E flower (lateral view) F flower (front view) G anthers and gynostemium H fruit I seeds. Photographed by Xinxin Zhu.

Figure 6. Holotype of Aristolochia yangii X. X. Zhu & J. S. Ma, sp. nov. (CSH- 0153654).

Figure 7. A-C Aristolochia pseudoutriformis X. X. Zhu & J. S. Ma, sp. nov. A leaves B flower (lateral view) C opened flower (showing the inside structure). D-F A. utriformis S. M. Hwang D leaves E flower (lateral view) F opened flower (showing the inside structure). G-I A. forrestiana J. S. Ma G leaves H flower (lateral view) I opened flower (showing the inside structure). J-L A. yangii X. X. Zhu & J. S. Ma. J leaves K flower (lateral view) L Opened flower (showing the inside structure). Photographed by Xinxin Zhu (A-C, G-L); Photographed by Lei Cai (D-F).