{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T07:26:42Z","timestamp":1780471602250,"version":"3.54.1"},"reference-count":97,"publisher":"Wiley","issue":"11","license":[{"start":{"date-parts":[[2014,11,1]],"date-time":"2014-11-01T00:00:00Z","timestamp":1414800000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["41210001"],"award-info":[{"award-number":["41210001"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002402","name":"Sun Yat-sen University","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100002402","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American J of Botany"],"published-print":{"date-parts":[[2014,11]]},"abstract":"<jats:p>\u2022 <jats:italic>Premise of the study:<\/jats:italic> The fossil record of alder (<jats:italic>Alnus<\/jats:italic>) is well known in the Cenozoic deposits throughout the northern hemisphere, based on numerous reports of the distinctive pollen, cone\u2010like infructescences, staminate inflorescences, and leaves. However, our understanding of the systematic position of these fossils relative to the modern phylogeny of the genus has been limited because most fossils were described from only one organ.<\/jats:p><jats:p>\u2022 <jats:italic>Methods:<\/jats:italic> We examined well\u2010preserved leaves and associated fruiting and staminate catkins from the middle Eocene, Clarno Formation, Oregon, USA by stereomicroscopy. In situ and dispersed pollen were cleaned with HF and acetolized for light and scanning electron microscopy.<\/jats:p><jats:p>\u2022 <jats:italic>Key results:<\/jats:italic> We reconstructed a new extinct species based on multiple organs and discuss significant phytogeographic and phylogenetic implications for <jats:italic>Alnus<\/jats:italic>. <jats:italic>Alnus clarnoensis<\/jats:italic> sp. nov. is described based on serrate leaves with 1\u20134 small teeth between each primary tooth, associated cone\u2010like fruiting catkins with fruits in situ, and associated slender pollen catkins bearing in situ 3\u2010 to 6\u2010pored pollen with arci between the pores. Combined investigations of each organ indicate that they probably derive from the same species and can be confidently attributed to subgenus <jats:italic>Alnus<\/jats:italic> Furlow based on leaf architecture and pollen pore number frequency.<\/jats:p><jats:p>\u2022 <jats:italic>Conclusions:<\/jats:italic> The Clarno fossils are most similar to the extant North American species of subgenus <jats:italic>Alnus<\/jats:italic> rather than to those from Asia and Europe, indicating that this modern subgenus was already distinct by the middle Eocene and that the intercontinental migration likely occurred earlier.<\/jats:p>","DOI":"10.3732\/ajb.1400228","type":"journal-article","created":{"date-parts":[[2014,10,31]],"date-time":"2014-10-31T22:12:53Z","timestamp":1414793573000},"page":"1925-1943","source":"Crossref","is-referenced-by-count":19,"title":["<i>Alnus<\/i> subgenus <i>Alnus<\/i> in the Eocene of western North America based on leaves, associated catkins, pollen, and fruits"],"prefix":"10.1002","volume":"101","author":[{"given":"Xiaoyan","family":"Liu","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Steven R.","family":"Manchester","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jianhua","family":"Jin","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2014,11]]},"reference":[{"key":"e_1_2_6_2_1","doi-asserted-by":"publisher","DOI":"10.1007\/BF02859135"},{"key":"e_1_2_6_3_1","first-page":"36","article-title":"An atlas of pollen of trees, shrubs of eastern Canada and the adjacent United States. 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