Interactions between plants and insects have shaped biodiversity at multiple ecological and evolutionary scales in both diverse taxonomic groups. Antagonistic interactions (such as herbivory) can impose strong selective pressures on plants, resulting in increased defense levels or diverse defense strategies. The nature and extent of plant defenses can vary both within and between species, potentially reflecting trade-offs between defense and growth strategy that are associated with environmental resources, known as the resource availability hypothesis. Global interspecific patterns may or may not reflect mechanisms acting within species at more restricted geographic scales. Here, we ask whether there is evidence for associations between growth strategies and defense levels, resource availability, and herbivore damage within three Helianthus species (H. giganteus, H. grosseserratus, and H. maximiliani) in a restricted region of the Upper Midwest in the USA. We measure growth traits, leaf defense traits, and leaf herbivore damage levels in wild sunflower populations to assess patterns across populations and in two common gardens to assess patterns within populations. We estimate associations between growth traits and defense traits, defense traits and environmental resources, and herbivore damage and environmental resources. Overall, we find that slower growth strategies are associated with increased levels of defenses, though these higher defense levels are not associated with lower-resource environments in wild populations, and some of these patterns are detected in the commons. We also find that herbivore damage levels are not associated with these resource levels. We conclude that defenses in these species are related to growth strategy even at this intraspecific scale and are largely in line with macroevolutionary patterns across the genus. Both defense levels and herbivore damage are not strongly related to resource availability, which may reflect limited amounts of resource variation in this restricted region and follow prediction within a general framework for intraspecific defense trait associations.

Climate change is leading to a less consistent snowpack in North America, and many species are affected by its loss. The question addressed in this study is how changes in temperature and moisture from the loss of snowpack separately affect overwintering fronds of the wintergreen fern Dryopteris intermedia (Muhl. ex Willd.) A. Gray. In a field study, the control had the snowpack left intact, the snow removal treatment had snow removed for the first and last 4 wk of winter, and the snow removal with barrier matched the snow removal treatment but with a moisture barrier over the plant. The control treatment had the most snow and the highest litter temperatures. Litter moisture was highest in the control and lowest in the snow removal treatment. Frond moisture was lower and frond damage was higher in the snow removal treatment than in the control and snow removal-with-barrier treatments. Frond damage was associated with the moisture but not the temperature in the environment around the frond. The loss of moisture can be as important as the lack of thermal insulation to damage experienced by D. intermedia when a snowpack is not present in winter.

We describe the pattern of vegetation change at three sites on a utility right-of- way, Exeter, Rhode Island, over 57 years. Trees and tall shrubs were cut from the right-of-way in 1963. The stumps were chemically treated in 1963 with 2,4,5-T. Select hardwood species were treated again from 1965 to 2022 targeting only the taller trees and shrubs. Unwanted small woody and herbaceous vegetation was treated with a 2% solution of Vastian, while Polaris (.250%), Escort, and Arsenal (.250%) were applied to unwanted weeds, grasses, and woody taxa. There has been an increase in the number of vascular plant species at each of the three sites, especially at Site 2, where the number of taxa, 28, is nearly double the 15 taxa identified at the site in 1965. There was a significant increase in the number of monocots in 2022, especially Poaceae, including Poa sylvestris A. Gray, a new Rhode Island record. No nonnative taxa were identified in 1965, while eight were present in 2022. Parsimony analysis reveals a branch break between Sites 1b and 2b and Sites 1a, 2a, 3a, and 3b. This is best explained by soil moisture, community development, and succession.

Species with lignotubers exhibit crown enlargements. In addition, many shoots and roots occur on surfaces of lignotubers. For lignotubers to form enlargements with many shoots and roots on their surfaces, they must produce many growth centers derived from the original vascular cambium. These growth centers arise from fragmented cambia and then remain within the lignotubers. In the present study, numbers and orientations of growth centers were determined within three species of lignotubers. Lignotubers were sawed in transverse and longitudinal slices to locate growth centers within the tissues. Lignotubers of Heteromeles arbutifolia and Frangula californica exhibited more vertically aligned growth centers with extensive shoot lobes while lignotubers of Eucalyptus nicholii exhibited a wider variety of orientations of growth centers. Lignotubers of H. arbutifolia and F. californica had 20 and 11 growth centers and more vertically aligned growth centers with extensive shoot lobes while lignotubers of E. nicholii had nearly 60 growth centers with fewer lobes.

Vines have insufficient cells with secondary cell walls to resist bending and stems buckle without external support. Some vine species have furrowed xylem that may have less mechanical support compared with vine species with normal xylem. Analyses were performed to quantify anatomical differences between vine stems with and without furrowed xylem. Seven species with and 13 species without furrowed xylem were analyzed with standard histological procedures. The first analysis was done with tissue samples of two furrowed xylem Aristolochia species that had stem areas from 5 to 30 mm². Xylem and sclerenchyma areas increased as stem areas increased so that the largest stem samples had the 20–30% xylem and 20% sclerenchyma areas. These percentages were typical for all the furrowed species. The second analysis compared 5 mm² area terminal stem samples of furrowed and nonfurrowed species. Mean xylem areas of samples with and without furrows were 1.28 and 2.11 mm², respectively. For these samples, results of a t-test produced no statistically significant differences between these two groups even though xylem comprised 18.7% and 35.0% for stems with and without furrows, respectively. All species with furrowed xylem had peripherally located sclerenchyma layer that formed a continuous ring within 10% of the stem surface, while vine species without furrowed xylem had no sclerenchyma. The sum of xylem and sclerenchyma areas in furrowed species were similar to the area of xylem in non-furrowed species. The data suggest that sclerenchyma cells provide significant resistance to stem bending in vines.

In the present study, six new records of fungi of the genus Geastrum Pers. are described in four different physiognomies of the Cerrado stricto sensu: Geastrum fimbriatum, G. lageniforme, G. morganiii, and G. hirsutum are the first records for the Brazilian Cerrado, being collected, respectively, in Typical Cerrado, Rupestrian Cerrado, Sparse Cerrado and Dense Cerrado. The specimen described as G. aff. rusticum is also the first record for the biome and was founded in Typical Cerrado. G. triplex is the second record for the Brazilian Cerrado and the first for the state of Bahia, found in physiognomies of Dense Cerrado. The taxa described present plates with photographs and micrographs for each species and a map for the collection locations.