Hedyotis puberulifolia Y.D.Xu & R.J.Wang, 2021

Xu, Yi-Da & Wang, Rui-Jiang, 2021, Hedyotis puberulifolia (Rubiaceae), a new species from Guangdong, China, Phytotaxa 502 (2), pp. 160-168 : 161-165

Hedyotis puberulifolia Y.D.Xu & R.J.Wang , sp. nov. ( Fig. 2 ).

Type: — CHINA. Guangdong: Jiexi County, Heshe Forestry Station , roadsides, 115°48’ E, 23°38’ N, elev. ca. 999 m, flowering and fruiting, long-styled flowers, 4 September 2020, Rui-Jiang Wang & Yi-Da Xu 6230 (holotype IBSC0858301 !; isotype IBSC0859880 !) .

Diagnosis:— A species similar to H. cantoniensis in having ovate to lanceolate leaves, indistinct secondary veins and terminal inflorescence, but differing from the latter by its puberulous stem, leaves, stipules, and thyrsoid inflorescence with monochaisal sub-axes and smaller flowers ( Table 3).

Perennial subshrub, 30–75 cm tall. Stem terete, densely puberulous, green to brown, slightly purple and sometimes sulcate when young. Leaves opposite, 4.0–10 × 1.8–4.0 cm, ovate to lanceolate, subcoriaceous, acute at apex, cuneate to rounded at base, leaf dark green and densely puberulous adaxially, more sparsely puberulous and greyish or sometimes purplish abaxially; midrib depressed adaxially and prominent abaxially, secondary veins usually 4–6 on each side, indistinct adaxially; subsessile to petiolate, petioles to 5 mm long. Stipules ca. 2.0 × 2.5 mm, triangular to ovate-triangular, acute at apex, sparsely glandular serrate at margin, puberulous abaxially. Inflorescence terminal or axillary in upper leaves, 2.7–6.0 cm long, thyrsoid with monochaisal sub-axes, puberulous; peduncles 1.0– 3.6 cm long; bracts 0.2–1.1 × 0.2–0.5 mm, lanceolate to ovate, bracteoles subulate. Flowers heterostylous, sessile to pedicellate, pedicels to 1 mm long. Hypanthium 1.5–2.0 mm long, obconic, puberulous; lobes 4, ca. 0.8 × 1.0 mm long, triangular to ovate-triangular, obtuse at apex. Corolla white; tube 2.0– 2.5 mm long, glabrous abaxially and and pubescent adaxially at throat; lobes 4, 1.4–1.5 × 0.9–1.0 mm long, ovate-triangular. Stamens 4, anthers ca. 0.7 mm long, oblong-linear. Ovary 2-celled, ovules numerous on axile placentas. Stigmas bilobed; styles puberulous. Longstyled flowers: stamens included, adnate to the middle of corolla tube, filaments ca. 0.4 mm long; styles ca. 3.6 mm long, stigmas ca. 0.5 mm long, ellipsoid, exserted. Short-styled flowers: stamens exserted, adnate to the throat of corolla tube, filaments ca. 0.8 mm long; styles ca. 1.4 mm long, stigmas ca. 0.7 mm long, clavate, included. Fruits capsular, ca. 2 × 2 mm, subglobose, entirely puberulous, diplophragmously dehiscent. Seeds plano-convex, ca. 0.6 mm, numerous, deep brown to black, with reticulate surface ( Fig. 3 ).

Phenology: —Flowering occurs in August and September; fruiting from September to November. Etymology: —The specific epithet refers to the puberulous leaves of this new species. Distribution and habitat: — Hedyotis puberulifolia is currently known from the eastern Guangdong Province,

China. It grows mainly under secondary broad-leaved forests, on dry slope or roadsides, at elevation range 650–1250

m. Main associated species are Melastoma dodecandrum Loureiro (1790: 274) and Lophatherum gracile Brongniart

(1829: 50), etc. *indicates that the sequences are newly added.

Palynology: —The pollens of Hedyotis puberulifolia are monads, isopolar and spheroidal, with 3-colporate apertures and microreticulum surface. The pollen size is 22.6 (21.4–25.0) × 20.8 (19.0–21.4) μm with P / E value 1.09 in short-styled flowers ( Fig. 4 : A – C) and 21.4 (20.2–23.8) × 21.0 (19.0–26.2) μm with P / E value 1.01 in long-styled flowers ( Fig. 4 : D– F).

Additional specimens examined (paratypes): — CHINA. Guangdong: Jieyang City, Jiexi County, Dayang Town , 20 Nov. 2014, Xian-Feng Zeng ZXF16000 ( CZH) ; Liangtian Town, Heshe Forestry Station, Mt. Liwangzhang , roadsides, 4 Sept. 2020, Rui-Jiang Wang & Yi-Da Xu 6216, 6228, 6229 ( IBSC) ; Wujingfu Town, Mt. Dayang , 18 Jul. 1921, F. A. McClure 7199 ( SYS) . Meizhou City, Fengshun County, Beidou Town , Tongziyang Forestry Station , on the hillside, in open forest, 14 Jul. 2000, Hua-Gu Ye 4271 ( IBSC) ; Dalonghua Town, Jingshui Temple, in mountainous region, in open forest, 27 Oct. 2017, Xian-Feng Zeng ZXF33688 ( CZH) ; Fengliang Town, Mt. Jiulongzhang, in mountainous region, roadsides, 25 Oct. 2017, Xian-Feng Zeng ZXF33502 ( CZH) ; Jingmen Town, Fengtian Village , on the hillside, in dense forest, 26 June 1957, Xue-Gen Li 201048 ( IBSC) ; Shatian Town, Mt. Tongguzhang , on top of the mountain, 12 July 2000, Hua-Gu Ye 4115 ( IBSC) ; same locality, in open forest, 19 Aug. 2009, Xian-Feng Zeng ZXF7255 ( CZH) .

Conservation status:— So far, mature individuals with a total of eight subpopulations, more than 1000 mature individuals of H. puberulifolia have been observed in Guangdong Province. This species mainly grows on the roadside of secondary broad-leaved forests, which are within the forest park or protected areas. Moreover, this plant has no any ornamental and medicinal uses and plausible threaten. Following the guidelines prepared by the IUCN Standards and Petitions Subcommittee (2019), the conservation of H. puberulifolia is evaluated as Least Concern.

Figures

FIGURE 2. Hedyotis puberulifolia. A: Habit; B: Leaves; C: Individuals; D: Inflorescence; E & F: Adaxial and abaxial surface of leaf, respectively; G: Stem and its transverse section; H: Stipule; I & J: Long-styled flower; K & L: Short-styled flower; M: Young capsules; N: Diplophragmous capsules; O: Seeds.

FIGURE 3. Seed morphology of Hedyotis puberulifolia (from Rui-Jiang Wang & Yi-Da Xu 6230). A: Ventral side; B: Dorsal side; C: Ornamentation.

FIGURE 4. Pollen morphology of Hedyotis puberulifolia (A–C from Rui-Jiang Wang & Yi-Da Xu 6216, short-styled flower; D–F from Rui-Jiang Wang & Yi-Da Xu 6230, long-styled flower) under SEM. A & D: Equatorial view; B & E: Polar view; C & F: Reticulate ornamentation.