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| Cotoneaster densiflorus M.W. Li, Q. Fan & W. B. Liao, in Li, Li, Lu, Mo, Ding, Chen, Lai, Zhang, Liao et Fan, 2023. |
Abstract
Cotoneaster densiflorus, a new species of Rosaceae from western Sichuan, China, is described and illustrated. Morphologically, we inferred that the new species belongs to Cotoneaster Ser. Salicifolii sensu Yü et al. (1974) in the Flora of China and Fryer and Hylmö (2009). This species is most similar to C. salicifolius, but differs in its leaf blade of ovate-lanceolate to obovate shape (vs. elliptic-oblong to ovate-lanceolate), smaller length-width ratio of 2.37 ± 0.31 (vs. 3.17 ± 0.32), slightly conduplicate (vs. not conduplicate), less lateral veins of 6–8 pairs (vs. 12–16 pairs), upper surface slightly rugose (vs. rugose), leaf margin plane (vs. revolute), lower surface densely grey tomentose (vs. grey tomentose, with bloom), greater corolla diameter of 7–9 mm (vs. 5–6 mm), styles 2 (vs. 2–3), pyrenes 2 (vs. 2–3), larger pollen grains P/E values of 2.05 ± 0.12 (vs. 1.19 ± 0.05) and leaf epidermis type W (vs. type I). Based on phylogenetic analysis of the whole chloroplast genome, C. densiflorus is sister to C. rhytidophyllus, but distantly related to C. salicifolius.
Key words: Anatomical, chloroplast genome, leaf epidermis, palynological, Ser. Salicifolii
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| Cotoneaster densiflorus sp. nov. A habit B leaf, adaxial surface C leaf, abaxial surface D flowers E vertical section of flower F petals G stamens H styles I fruiting branch J pome K transverse section of pome L pyrenes. Illustration by Zhengmeng Yang based on living field-collected materials (Q. Fan & M.W. Li 14925, M.W. Li 20230617007). |
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| Cotoneaster densiflorus sp. nov. A habitat B habit C branchlets D petal, stamen, style, and vertical section of flower E ovate-lanceolate to obovate shape of leaves F leaf, abaxial surface G 2 pyrenes per fruit H inflorescence I fruiting branch. |
Cotoneaster densiflorus M.W. Li, Q. Fan & W. B. Liao, sp. nov.
Diagnosis: Morphologically, Cotoneaster densiflorus is similar to C. salicifolius, but differs in its leaf blade of ovate-lanceolate to obovate shape (vs. elliptic-oblong to ovate-lanceolate), smaller length-width ratio of 2.37 ± 0.31 (vs. 3.17 ± 0.32), slightly conduplicate (vs. not conduplicate), fewer lateral veins of 6–8 pairs (vs. 12–16 pairs), upper surface slightly rugose (vs. rugose), leaf margin plane (vs. revolute), lower surface densely grey tomentose (vs. grey tomentose, with bloom), greater corolla diameter of 7–9 mm (vs. 5–6 mm), styles 2 (vs. 2–3) and pyrenes 2 (rarely 3). Although there is a closer phylogenetic relationship between the new species and C. rhytidophyllus, it is easy to distinguish them by the indumentum color of branchlets, leaves and inflorescences, rugose leaf upper surface, fruit shape and pyrenes number. See Table 2, Figs 1, 2 for a detailed comparison.
Etymology: The specific epithet refers to the compact compound corymbs with (5–)10– to 50–(61)-flowered per inflorescence.
Mingwan Li, Dan Li, Mengfei Lu, Shuangfeng Mo, Shen Ding, Yuanyuan Chen, Yong Lai, Dangquan Zhang, Wenbo Liao and Qiang Fan. 2023. A New Species of Cotoneaster (Rosaceae) from western Sichuan, China. PhytoKeys. 236: 39-52. DOI: 10.3897/phytokeys.236.111819
