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An anatomically preserved moss gametophyte has been discovered in a marine carbonate concretion from the Baculites Hill locality, James Ross Island, Antarctica. The concretion is derived from the Late Cretaceous Beta Member of the Santa Marta Formation, dated as early to middle Campanian (ca. 80 Ma). The moss has actinomorphic stems with alternate branching, spiral, patent leaf arrangement and large numbers of attached rhizoids. The largest stem is 210 mm in diameter with the largest branch measuring up to 3.7 mm long and 90–100 mm wide. Most stems appear to contain a distinct conducting strand. Cross sections show that the leaves are strongly plicate with a simple D-shaped costal anatomy and unistratose laminae typically with bistratose margins. Leaves range from 650–700 mm wide and at least 700 mm long. The costa appears percurrent, 90 mm wide and 55 mm thick. Laminar cells are elongate, rhomboidal, L/W ¼ 5:1. No ornamentation or papillae have been observed on the upper medial cells of the leaf. These fossils show leaf morphology and costal anatomy similar to several orders of acrocarpous mosses, in the Dicranidae including species of the family Rhabdoweisiaceae. While the combination of characters does not fit into any known genus, it suggests that this moss represents a fossil member of the Dicranales s.l. To date, this represents the most completely preserved moss gametophyte from Gondwana. 

More than 20,000 siderite concretions from the Mazon Creek area of northern Illinois, United States are housed in the paleobotanical collections of the Field Museum. A large proportion contain fossil plants of Middle Pennsylvanian age that often have excellent three-dimensional morphology and sometimes anatomical detail. Approximately eighty plant taxa have been recognized from the Mazon Creek Lagerstätte, but few have been studied in detail, and in some cases the systematic affinities of these fossils need reevaluation. The three-dimensional (3D) preservation of Mazon Creek fossil plants makes them ideal candidates for study using x-ray micro-computed tomography (μCT), and here we apply these techniques to more accurately reconstruct the morphology of specimens of Tetraphyllostrobus Gao et Zodrow and Crossotheca Zeiller. The mineralogical composition of the fossil plant preservation was studied using elemental maps and Raman spectroscopy. In-situ spores were studied with differential interference contrast, Airyscan confocal super-resolution microscopy, and scanning electron microscopy, which reveal different features of the spores with different degrees of clarity. Our analyses show that μCT can provide excellent detail on the three-dimensional structure of Mazon Creek plant fossils, with the nature of associated mineralization sometimes enhancing and sometimes obscuring critical information. Results provide guidance for selecting and prioritizing fossil plant specimens preserved in siderite concretions for future research. 

The genus Surangea Chitaley et Sheikh, based on permineralized specimens from the Deccan Intertrappean Beds of central India, was originally considered to represent a fern megasporangium. Reexamination of original material and new specimens has revealed that the structures are capsular fruits with well-defined seeds, rather than megasporangia. We describe Surangea fruits in detail, based on peels and micro-CT scanning, and document its distribution among multiple localities of the Deccan Intertrappean Beds. The fruits are pentacarpellate septicidal capsules with ~8–12 seeds per locule. The seeds are prominently ornamented with parallel ridges and have a curved embryo/endosperm cavity and a prominent aril. This set of features indicates eudicotyledonous affinities for Surangea. In particular, the combination of septicidal capsules, axile placentation and arillate campylotropus seeds suggests affinity with the order Myrtales, but it does not fit cleanly within an extant family. Surangea fruits add to the diversity of angiosperms known from this late Maastrichtian flora. It joins several other fruit types known from the Deccan flora that do not fall neatly into extant families, possibly representing parts of an endemic community that succumbed to environmental stress associated K-Pg boundary events and/or subsequent northward rafting of the Indian subcontinent. 

Summary Cunoniaceae are important elements of rainforests across the Southern Hemisphere. Many of these flowering plants are considered Paleo‐Antarctic Rainforest Lineages that had a Gondwanan distribution since the Paleocene. Fossils of several modern genera within the family, such asCeratopetalum, have indicated biogeographical connections between South America and Australia in the Cenozoic.Here, we report a dramatic geographical range extension forCeratopetalum, and Cunoniaceae as a whole, based on two exceptionally preserved fossil winged fruits from Campanian (c. 82–80 Ma old) deposits on Sucia Island, Washington, USA. The fossils were studied using physical sectioning, light microscopy, micro‐computed tomography scanning and multiple phylogenetic analyses.The fossil fruits share diagnostic characters withCeratopetalumsuch as the presence of four to five persistent calyx lobes, a prominent nectary disk, persistent stamens, a semi‐inferior ovary and two persistent styles. Based on morphological comparisons with fruits of extant species and support from phylogenetic analyses, the fossils are assigned to a new speciesCeratopetalum suciensis.These fossils are the first unequivocal evidence of crown Cunoniaceae from the Cretaceous of North America, indicating a more complicated biogeographical history for this important Gondwanan family. 

Summary Plant carbon isotope discrimination is complex, and could be driven by climate, evolution and/or edaphic factors. We tested the climate drivers of carbon isotope discrimination in modern and historical plant chemistry, and focus in particular on the relationship between rising [CO₂] over Industrialization and carbon isotope discrimination.We generated temporal records of plant carbon isotopes from museum specimens collected over a climo‐sequence to test plant responses to climate and atmospheric change over the past 200 yr (includingPinus strobus,Platycladus orientalis,Populus tremuloides,Thuja koraiensis,Thuja occidentalis,Thuja plicata,Thuja standishiiandThuja sutchuenensis). We aggregated our results with a meta‐analysis of a wide range of C₃plants to make a comprehensive study of the distribution of carbon isotope discrimination and values among different plant types.We show that climate variables (e.g. mean annual precipitation, temperature and, key to this study, CO₂in the atmosphere) do not drive carbon isotope discrimination.Plant isotope discrimination is intrinsic to each taxon, and could link phylogenetic relationships and adaptation to climate quantitatively and over ecological to geological time scales.