A new species of Coccoloba P. Browne (Polygonaceae) from the Brazilian Amazon with exceptionally large leaves

ABSTRACT We describe and illustrate a new species of Coccoloba (Polygonaceae), named Coccoloba gigantifolia, from the Brazilian Amazon. It resembles Coccoloba mollis Casar, but differs from the latter species by its much larger leaves in the fertile branches. The species has only been recorded in the Madeira River basin, in the states of Amazonas and Rondônia, in the central and southwestern Brazilian Amazon. The description was based on herbarium material, cultivated plants, and individual trees in their natural habitat. We provide illustrations, photographs, and an identification key with morphological characteristics that distinguish the new taxon from the other two related taxa of the Coccoloba sect. Paniculatae, as well as comments on the geographic distribution and conservation status of the species.

摘要：本文记述并图示了产自巴西亚马逊地区的蓼科（Polygonaceae）海葡萄属（Coccoloba）一新种，命名为巨叶海葡萄（Coccoloba gigantifolia）。该新种与软叶海葡萄（Coccoloba mollis Casar）形态相似，但孕枝上的叶片显著大于后者。目前该物种仅记录于巴西亚马逊中部及西南部的亚马孙州（Amazonas）与朗多尼亚州（Rondônia）境内的马德拉河（Madeira River）流域。本研究基于标本馆馆藏标本（herbarium material）、栽培植株及原生境中的野生个体完成该新种的记述，同时提供了该新类群（taxon）的形态特征图示与照片，并编制了可将该新类群与海葡萄属圆锥花序组（Coccoloba sect. Paniculatae）其余2个近缘类群区分开的检索表，此外还对该物种的地理分布及保护现状进行了讨论。