Styrax macrocarpus Cheng (Cheng 1938: 398)

Ruan, Yu-Qing, Yu, Yu-Long, Yu, Fen, Deng, Guo-Xing, Liu, Yu-Lin, Wu, Xue-Hui & Tang, Ming, 2019, Reinstatement of the Chinese endemic species Styrax zhejiangensis, PhytoKeys 133, pp. 105-113 : 105

Styrax macrocarpus Cheng (Cheng 1938: 398) Fig. 1B , 4 , 5 A2, B2, C2, D2

Type.

CHINA. Hunan: Yizhang, Mang Mountain, 800 m, 21 August 1937, W. C. Cheng 7000 [from protologue] (holotype PE00027927!; isotype PE 00027979!)

Description.

Trees 6 –9(– 12) m tall, with a single stem, deciduous. Branchlets subterete, densely gray-brown stellate-pubescent, glabrescent. Leaves alternate, two most proximal leaves on each shoot subopposite to opposite; leaf blade broadly elliptic to ovate-oblong, 5.5-15.0 × 3.0-6.0 cm, papery, glabrous but veins stellate-pubescent, elliptic to obovate-elliptic; apex acute; base cuneate, broadly cuneate or rounded; margin subentire or apically slightly serrate; secondary veins 6 to 10 pairs, tertiary veins subparallel; adaxially plane or slightly sunken, abaxially raised. Petiole 2-5 mm long. Pedicel 9-13 mm long, densely white-stellate-tomentose; bracteoles 6-10 mm long, ovate-lanceolate. Flowers solitary, axillary, opening before leaves. Calyx 5-8 × 6-9 mm, membranaceous, densely gray-stellate-tomentose and sparsely stellate-pubescent; teeth 5 or 6, deltoid, unequal, 2-3 mm, subglabrous. Corolla diameter 6.0-7.5 cm, white, tube 3-4 mm long; lobes 6 or 7, elliptic-obovate, 2.8-3.8 × 1.5-2.5 cm. Stamens 11 to 15, 14-16 mm long, shorter than corolla; filaments 7-10 mm long, basally densely white-stellate-pubescent; anthers 5-7 mm long. Fruit solitary, axillary, ovoid, 2-3 × 2.0-2.5 cm, densely gray-stellate-pubescent, apex shortly pointed. Seeds ovoid-ellipsoid, irregularly rugose, glabrous.

Distribution and habitat.

Styrax macrocarpus is distributed between southeastern Hunan and western Guangdong ( Fig. 2 ). It grows in sparse forests, valleys or at forest margins at elevations between 130 and 230 m a.s.l.

Phenology.

Flowering from mid- to late April and fruiting in August and September.

Additional specimens examined.

CHINA. Hunan: Yizhang, S.H. Chun 2889 (AU, IBK, IBSC, KUN, PE), 5408 (IBSC), Central South Forestry Institute internship team 02-3 195 (CSFI), M.S Huang 112743 (IBSC), H.S. Liao 15727 (CSFI), P.H. Liang & X.H. Xu 85107 (IBK, IBSC), S.R. Lin & K.W. Liu 50285 (CSFI), X.Q. Liu 28884 (IBK, IBSC, NAS, PE), Y.Q. Ruan & Y.L. Liu 34 (JXAU), J.G. Xiao 4142 (CSFI), anonymous 137 (IBSC), anonymous 1017 (CSFI). Guangdong: Fengkai, G.L. Shi 14815 (IBSC), Q.S. Yue 5185 (IBSC); Ruyuan, L. Wu & Y. Tong 3192 (IBSC), Z.L. Chen 30610 (IBSC).

Notes.

The two specimens collected from Mengla County, Yunnan (Y. M. Xia 245, HITBC) and Yulin, Guangxi (Y.S. Wu 0289, IBK) respectively, which were also designated as Stytax macrocarpus on the sheets, are confirmed to be wrongly identified and should be S. chinensis ( Liang 1980: 230), a widely distributed species in the southernmost provinces of China such as Guangdong, Guangxi, Yunnan, Fujian, as well as Southeast Asia. S. chinesis could be easily distinguished from S. macrocarpus by its bigger (8-23 × 3-12 cm vs 5.5-15.0 × 3.0-6.0 cm), thick-leathery leaves (vs papery) leaves.

Figures

Figure 1. Lectotype sheet of Styrax zhejiangensis, China, Zhejiang, Jiande, X. Y. He 29344 (IBSC) (A) and holotype sheet of S. macrocarpus, China, Hunan, Yizhang, Mang mountain, W. C. Cheng s. n. (PE) (B).

Figure 2. Distribution map of Styrax zhejiangensis ([INSERT FIGURE 003]) and S. macrocarpus.

Figure 4. Styrax macrocarpus (Yizhang, Hunan, China) A habitat and habit; red arrow indicates S. macrocarpus B inflorescence C leaf blades in adaxial (left) and abaxial (right) view D flower (top view) E flower (back view) F flower (side view) G corolla lobes H sepals (two sepals pulled apart at the lobe margins of one calyx) I stamens. Photographed by Yu-Qing Ruan and Ming Tang.

Figure 5. Morphological comparison between Styrax zhejiangensis (A 1, B 1, C 1, D 1) and S. macrocarpus (A 2, B 2, C 2, D 2). A 1, A 2 Flower B 1, B 2 corolla lobes C 1, C 2 stamens D 1, D 2 seed (Note the enlarged stellate trichomes in the red circle in figure D 1). Photographed by Yu-Qing Ruan and Ming Tang.