Ulva (Ulvophyceae, Chlorophyta) is common in intertidal environments and can also be found in freshwater ecosystems. The difficulty to morphologically identify Ulva species due to cryptic diversity and morphological plasticity has caused a taxonomic conundrum. Fortunately, molecular data have begun to unravel a better understanding of its diversity. Here, we present a molecular analysis with 247 samples of Ulva from the Gulf of Mexico and Atlantic USA based on chloroplast (rbcL and tufA) and nuclear (ITS1‐5.8S‐ITS2) molecular markers. Twenty‐four Ulva taxa had previously been reported for this area based on morphology and earlier molecular studies mostly from Northeastern USA and Canada. In this study, sixteen Ulva clades were identified representing 13 named clades and putatively three undescribed species. Only nine of the 24 taxa previously reported for the Western Atlantic were confirmed. Four species were identified for the first time in the U.S. East and Gulf Coast (U. aragoënsis, U. californica, U. meridionalis, and U. tepida). This study provides a foundation for future research on Ulva in this area and reiterates the necessity of using molecular‐assisted identifications for this group.

中文翻译：

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根据分子数据，来自美国东部和墨西哥湾沿岸的绿色大型藻类Ulva（Ulvophyceae，Chlorophyta）的多样性

Ulva（Ulvophyceae，Chlorophyta）在潮间带环境中很常见，也可以在淡水生态系统中找到。由于隐秘的多样性和形态可塑性，很难在形态上鉴定Ulva物种，这导致了分类学上的难题。幸运的是，分子数据已开始使人们更好地了解其多样性。这里，我们目前有247个样本的分子分析石莼从墨西哥和美国大西洋的海湾基于叶绿体（RBC L和TUF A）和核（ITS1-5.8S-ITS2）分子标记。二十四乌尔瓦先前已经根据形态学和较早的分子研究（主要来自美国东北部和加拿大）对这一地区进行了分类。在这项研究中，鉴定出16个Ulva进化枝，代表13个命名进化枝和推定的3个未描述物种。在先前报告的西大西洋的24个分类单元中，只有9个被确认。四个品种被认定为在美国东部和墨西哥湾沿岸地区（第一次U.aragoënsis，U.夜蛾，U.鲇和U. tepida）。这项研究提供了对未来的研究奠定了基础，石莼在这一领域，并重申利用分子辅助标识该组的必要性。