Chrysosplenium sangzhiense Hong Liu, 2021

Fu, Long-Fei, Yang *, Tian-Ge, Lan, De-Qing, Wen, Fang & Liu, Hong, 2021, Chrysosplenium sangzhiense (Saxifragaceae), a new species from Hunan, China, PhytoKeys 176, pp. 21-32 : 21

Chrysosplenium sangzhiense Hong Liu sp. nov. Figs 3 , 4 , 5

Remarks.

Similar to Chrysosplenium grayanum , C. nepalense , C. sinicum and C. cavaleriei (Table 2 ). C. sangzhiense differs from C. grayanum in its usually fewer cauline leaves, a square flowering stem and red-brown seeds; from C. nepalense it differs in its usually fewer cauline leaves, a square flowering stem and conspicuously unequal capsule lobes; from C. sinicum it differs in producing sterile shoots from all leaf axils, an absence of basal leaves, larger cauline leaves, and red-brown seeds; and from C. cavaleriei it differs in its erect sepals and absent disc.

Type.

China. Hunan: Badagongshan National Nature Reserve , Sangzhi County, 29°47'10"N, 110°5'33"E, under broadleaved forests and near the stream in a mountain area at ca 1,220 m altitude, 22 April 2017, Hong Liu HSN07449 (holotype HSN; isotypes HSN, IBK) .

Description.

Perennial herbs, 10-25 cm tall. Root fibrous and robust. Rhizome long creeping without stolons or bulbs. Basal leaves absent. Sterile shoots well developed, arising from all leaf axils, round in cross-section, 5-15 cm long at anthesis, later elongate and decumbent, up to 50 cm long, rooting at nodes, without forming a rosette. Leaves of sterile shoots opposite, isophyllous, always ca 8 at anthesis, dark purple, petiole 6-10 mm long, blade 10-30 × 10-25 mm, rounded, glabrous, apex obtuse, margin obtusely dentate (10-16 teeth), base broadly cuneate; post-anthesis 10-30 or more, green, petiole 6-10 mm long, blade 20-35 × 15-20 mm, rounded or ovate, glabrous, apex obtuse, margin obtusely dentate (12-20 teeth), base broadly cuneate. Cauline leaves 4-6 (2-3 pairs), opposite, petiole 6-10 mm long; blade 6-13 × 5-12 mm, rounded or broadly ovate, glabrous, apex obtuse, margin obtusely dentate (10-14 teeth), base broadly cuneate. Flowering stem(s) erect, branched, 10-23 cm tall, glabrous, purple, square in cross-section. Inflorescence 8-25-flowered cyme, dense, 1.4-9 cm long, 5-10 cm in diam.; bracteal leaves yellow-green, triangular arrangement and unequal, the middle one larger, petiole 2-8 mm long, blade 4-15 × 7-10 mm, subrounded, glabrous, apex obtuse, margin obtusely dentate (6-12 teeth), base broadly cuneate; Flowers tetramerous, actinomorphic; sepals 4 (2 pairs), erect, yellow in flowering phase but turn green in fruiting time, 2-3 × 2-3 mm, broadly ovate, apex obtuse; disk absent; stamens 8, homostylic, 1-2 mm long, shorter than sepals; filaments slender, ca 1 mm long; anther yellow, 2-locular, longitudinally dehiscent; ovary 2-locular, semi-inferior; stigma 2; styles erect, ca 1-2 mm long. Fruit a capsule, 5-7 mm long, green, smooth, 2-lobed (horn-shaped), conspicuous unequal, dehiscent along the adaxial suture; seeds numerous, reddish brown, sub-ovoid, a raphe on one side, 650-800 × 600-750 μm, papillose.

Etymology.

Chrysosplenium sangzhiense is named after the type locality, Sangzhi County, Hunan Province, China.

Vernacular name.

sāng zhí jīn yāo (Chinese pronunciation); 桑植金腰 (Chinese name).

Conservation status.

At present, Chrysosplenium sangzhiense is only known from a single locality (IUCN criterion D2). At this locality, the population is ca 500 mature individuals (IUCN criterion D1) growing in at least ten patches within a nature reserve. Using the IUCN methodology, C. sangzhiense would be classed as Vulnerable (VU), however no plausible threat could be found to confirm its status as the population is located within a protected area and not under threat in the near future. In addition, considering that the surrounding area has not been completely explored, there may be hitherto undocumented additional populations. For these reasons the Global Species Conservation Assessment for C. sangzhiense is Least Concern (LC).

Figures

Figure 3. Illustration of Chrysosplenium sangzhiense Hong Liu, sp. nov. A habit in flowering phase B non-flowering stem C inflorescence with flowers D flower E capsule F seeds.

Figure 4. Plate of Chrysosplenium sangzhiense Hong Liu, sp. nov. A habitat B habit in flowering phase C habit in non-flowering phase D flowering stem E inflorescence with flowers (Photos by Hong Liu).

Figure 5. Macro- and micro-morphology of Chrysosplenium spp. A C. sangzhiense, habit (A 1), inflorescence with flowers (A 2), scanning electron micrograph (SEM) of seed 200 x (A 3), 1,000 x (A 4) B C. grayanum, habit (B 1), inflorescence with flowers (B 2), SEM of seed 150 x (B 3), 1,000 x (B 4) C C. nepalense, habit (C 1), inflorescence with flowers (C 2), SEM of seed 150 x (C 3), 1,000 x (C 4) D C. sinicum habit (D 1), inflorescence with flowers (D 2) SEM of seed 150 x (D 3), 1,000 x (D 4) (Photos by Hong Liu).