Abstract Staphylea has abundant isolated seeds in the fossil record, but no fossil fruits of this genus have been confirmed before. In this paper, we report a capsular fruit of Staphylea from the Oligocene Renova Formation of Woodworth, western-central Montana, USA. Detailed investigation of this fruit gives new insights on the phylogenetic and biogeographic history of the genus. Morphological comparison with modern Staphylea fruits shows its closest resemblance to the extant Asian species, S. bumalda DC., which is similar in fruit shape, size, and pericarp venation, but differs by the angle of interlobal sinus and the stipe development. We establish a new fossil species, S. woodworthensis Zhu & Manchester sp. nov. for this fossil fruit. This discovery indicates that Staphylea was already established in western North America at least by the Oligocene, which is inconsistent with the recent interpretation of a late Oligocene origin of the genus in Europe. The distribution of fossils indicates an earlier diversification of Staphylea, along with other staphyleaceous genera, back to early Paleogene in North America. The genus subsequently retracted its range to the east and south in North America as evidenced by younger fossils and its modern geographic range.

中文翻译：

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美国蒙大拿渐新世葡萄属（葡萄科）的果实

摘要 葡萄球菌在化石记录中具有丰富的分离种子，但该属的果实化石此前未得到证实。在本文中，我们报告了来自美国蒙大拿州中西部伍德沃思渐新世 Renova 组的葡萄球菌的荚膜果实。对这种水果的详细研究为该属的系统发育和生物地理历史提供了新的见解。与现代葡萄球菌果实的形态学比较显示其与现存的亚洲物种 S. bumalda DC. 最相似，其果实形状、大小和果皮脉络相似，但在叶间窦的角度和菌柄发育方面有所不同。我们建立了一个新的化石物种，S. woodworthensis Zhu & Manchester sp。十一月 对于这种化石果实。这一发现表明葡萄球菌至少在渐新世时期已经在北美西部建立，这与最近对该属在欧洲的渐新世晚期起源的解释不一致。化石的分布表明金黄色葡萄球菌以及其他葡萄球菌属的早期多样化，回到北美的古近纪早期。该属随后将其分布范围缩小到北美的东部和南部，年轻的化石及其现代地理范围证明了这一点。