Abstract Here we describe the Leonardian-age flora from “Emily Irish” (Russell Ranch), a small oxbow lake deposit, which is believed to be one of the most extensively collected, single-excavation floras of this age from any place in the world, including ca. 5200 hand specimens housed at the US National Museum of Natural History. The flora is dominated by a mixture of xeromorphic and meso-hygromorphic elements. The xeromorphs include conifers, taeniopterids, cordaitaleans, and noeggerathialeans. The mesomorphic-to-hygromorphic elements include marattialean tree ferns, sphenopsids, lycopsids, callipterids, and medullosan pteridosperms. This co-dominance of hygromorphic and xeromorphic elements is made especially conspicuous by the intimate co-mingling of plant remains from each group on the same hand specimens, and by the relative preservation-state of the macrofossils, which does not differ between the two groups. These observations suggest that they inhabited the same landscape immediately surrounding the depositional environment, and were likely only differentiated by microhabitat. We suggest that the Emily Irish flora grew under seasonally dry climate, but that areas adjacent to the lake and feeder streams retained sufficient moisture to support patches of taxa requiring consistently high soil moisture. These patches, thus, were embedded within a landscape of periodic moisture deficit that supported vegetation composed mostly of xeromorphic elements. This is more likely than requiring the xeromorphic taxa to be transported to the site from extrabasinal habitats, the nearest of which were hundreds of kilometers away at the time the deposit formed.

中文翻译：

---

来自西赤道盘古地区植物丰富地区（美国德克萨斯州下二叠纪艾米莉爱尔兰遗址）的混合湿态至异形植物群的优势多样性结构

摘要 在这里，我们描述了来自“艾米丽爱尔兰”（罗素牧场）的莱昂纳德时代植物群，这是一个小型牛轭湖沉积物，被认为是这个时代从世界任何地方收集最广泛的单一挖掘植物群之一。 ，包括约。美国国家自然历史博物馆收藏的 5200 个手部标本。植物区系以拟干和中湿型元素的混合物为主。异形包括针叶树、绦虫、cordaitaleans 和 noeggerathialeans。中胚型到湿胚型的元素包括蕨类植物、蝶类、石蒜类、蝾螈和髓质蕨类植物。由于同一手标本上每组植物遗骸的密切混合，这种湿态和拟态元素的共同优势尤为明显，并且通过宏观化石的相对保存状态，这在两组之间没有区别。这些观察结果表明，它们居住在紧邻沉积环境的同一景观中，并且可能仅因微生境而有所不同。我们建议艾米莉爱尔兰植物群在季节性干燥的气候下生长，但靠近湖泊和支流的地区保留了足够的水分，以支持需要持续高土壤水分的分类群。因此，这些斑块被嵌入在一个周期性水分亏缺的景观中，该景观支持主要由干形元素组成的植被。这比要求将异形类群从盆地外栖息地运送到现场更有可能，其中最近的栖息地在沉积物形成时距离数百公里。