Dimetia brevipetiolata (Spermacoceae: Rubiaceae): A new species from Guangxi, China Author Zhang, Ying Key laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong 510650, China & University of Chinese Academy of Sciences, Beijing 100049, China Author Jiang, Guo-Bin Key laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong 510650, China & University of Chinese Academy of Sciences, Beijing 100049, China Author Wang, Rui-Jiang Key laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong 510650, China text Phytotaxa 2020 2020-01-06 428 1 43 50 http://dx.doi.org/10.11646/phytotaxa.428.1.4 journal article 10.11646/phytotaxa.428.1.4 1179-3163 13875952 Dimetia brevipetiolata R. J. Wang , sp. nov. , 短ijkª4 Figs. 1 & 2 . Type: CHINA . Guangxi Zhuang Autonomous Region , Rong county , Shizhai Town , Duqiaoshan Scenic Area , riverside, long-styled flowers, 22º47’37.5” N , 110º36’18.4” E , ca. 100 m a.s.l. , 02 April 2013 , Rui-Jiang Wang & Shu-Jun Deng 2304 ( holotype : IBSC0847225 ; isotypes : IBSC ) . Dimetia brevipetiolata is similar to D. scandens with respect to its terete stem, lanceolate and thick papery leaves, indistinct secondary veins and compound-cymose inflorescences, but differs in the prostrate and herbal habit (vs. scandent and woody), subsessile leaf (vs. subsessile-5.0 mm long petioled), rounded leaf base (vs. acute to cuneate), nearly glabrous corolla (vs. densely villous adaxially) and indehiscent capsules (vs. dehiscent) ( Table 2 ). TABLE 2. Morphological comparison between Dimetia brevipetiolata and its closely related species.

Characters	D. brevipetiolata	D. scandens	D. ampliflora
Habit	Semi-prostrate herb	Climbing, twining, or scandent subshrub	Climbing, twining, or scandent subshrub
Height (cm)	20–30	(30–) 60–150	80–100
Leaf size (cm)	1.8–5.0 × 1.0–2.5	5.0–12 × 1.5–4.5	2.0–7.0 × 0.8–3.0
Leaf shape (cm)	Lanceolate or narrowly elliptic	Oblong-lanceolate, elliptic, narrowly elliptic, or elliptic-oblong	Lanceolate, broadly lanceolate, elliptic, or narrowly elliptic
Leaf base	Rounded	Acute to cuneate	Cuneate to obtuse
Petiole length (mm)	Subsessile	(Sub)sessile or to 5.0	2.0 to 6.0
Stipules	Triangular, apex acute	Truncate or triangular	Truncate to triangular, apex lacerate into 3–5 triangular to linear bristles
Secondary veins	3 (–4) pairs	3–5 pairs	3–4 pairs
Inflorescence	Compound-cymose	Cymose to compound-cymose	Compound-cymose
Corolla (mm)	White, tube 2.1–3.0	White or yellow, tube 1.0–2.0	White, tube 2.0
Corolla indument	Nearly glabrous	Glabrous abaxially, densely villous adaxially	Abaxially granular-puberulent
Calyx	Sparsely pubescent abaxially; lobes triangular with apex acute	Glabrous; lobes triangular and thickened	Glabrous to densely hirtellous; lobes lanceolate to spatulate
Capsules	Ellipsoid to subglobose, glabrous; indehiscent	Ellipsoid to subglobose, glabrous; dehiscent	Subglobose to ovoid, glabrous to densely hirtellous; dehiscent

Description Semi-prostrate herbs , 20–30 cm tall, glabrous. Stems terete, up to 3 mm in diameter, pubescent at young branches but glabrous with growing. Leaves opposite, subsessile; blade thick papery, glabrous, lanceolate or narrowly elliptic, apex acute or shortly acuminate, base rounded, 1.8–5.0 × 1.0– 2.5 cm ; midrib depressed and pubescent adaxially, prominent and glabrous abaxially; secondary veins usually in 3 (–4) pairs, indistinct on both sides. Stipules interpetiolar, fused to petiole bases, triangular, apex acute, 1.2–1.3 × 0.2–0.4 mm . Inflorescence terminal, compound cyme; peduncles sparsely pubescent, 0.5–2 cm long, terete; bracts lanceolate, 0.5–1.8 × 0.2–0.5 mm ; bractlets triangular, 0.4–0.9 × 0.1–0.3 mm . Flowers heterostylous; pedicels pubescent, subsessile or up to 3 mm long. Calyx sparsely pubescent abaxially, hypanthium obconic, 0.8–1.2 mm long; lobes 4, triangular, apex acute, 0.7–1.3 × 0.5–1 mm . Corolla white, tube 2.1–3.0 mm long, sparsely pubescent at throat; lobes 4, oblong-lanceolate, 1.1–2.7 × 0.8–1.5 mm . Stamens 4, anthers oblong-linear, ca. 0.6 mm long. Stigma bilobed, papillate, 0.5–0.9 mm long. Long-styled flowers: styles exserted, 3.5–4.5 mm long; stamens included, adnate to the middle of corolla tube; filaments short, ca. 0.2 mm long. Short-styled flowers: styles included, 1.4–2.0 mm long; stamens exserted, adnate to the throat of corolla tube; filaments ca. 2.3 mm long. Capsules ellipsoid to subglobose, or ovoid, 2.0–2.5 × 1.5–2.0 mm, glabrous, with persistent calyx limbs, protruded and indehiscent at apex. Seed numerous, minute, ca. 0.3 mm , deep brown, with angled and reticulate surface. Phenology: Flowering occurs in March–April, fruiting in May–July.