Castanea Archives

Articles published in Castanea from 2008 to present (Volumes 75 to 84) may be downloaded directly from our archives below.

SABS members can use the JSTOR portal on this page to access Castanea articles from Volumes 1 through 80.

2010 Archives

2009 Archives

Volumes 68 (2002) – Current

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Volumes 1 (1937) – 80 (2015)

Articles from our Current Issue

Vascular Plant Flora of Stone Mountain Park, DeKalb County, Georgia, Based on Digitized Specimens in the University of Georgia Herbarium (GA)

Stone Mountain in DeKalb County, Georgia, is a large exposed granite monolith, 514 m (1,686 ft) above sea level and covering 230 ha (560 ac). This monadnock is located in the southwestern portion of Stone Mountain Park, comprising 1,300 ha (3,212 ac) owned by the state of Georgia. Recent specimen digitization efforts at the University of Georgia Herbarium (GA) have greatly facilitated capture of data from historic vouchers collected from this park. Based on these newly available data, the goals of this project were to (1) prepare a vouchered species list for the park, (2) produce a vegetation map based on georeferenced label data, and (3) identify all plant collectors and track collection activities through time and taxon focus. Eighty-one individuals and teams collected 1,207 vouchers (709 species) dated 1846–2011. The largest families were Asteraceae (96 spp.), Poaceae (70 spp.), Fabaceae (49 spp.), Cyperaceae (33 spp.), Rosaceae (21 spp.), and Lamiaceae (20 spp.). Approximately 17.5% of the species were exotic. Eighteen species are listed as rare in Georgia with state protection status conferred on five species; Gratiola amphiantha (threatened) and Isoetes melanospora (endangered) are also federally ranked. Specimen label data and various map resources were used to plot the locality of each specimen. Habitat data were recorded on 808 specimen labels, allowing assignment of 612 taxa to at least one of five general habitat types. GPS coordinates, assigned through GeoLocate, were combined with habitat data and infrared imagery to create a general vegetation map of Stone Mountain Park

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The Vascular Flora of Orchard Knob Reservation, Chattanooga, Tennessee

Orchard Knob is a 2.5 ha National Military Park near downtown Chattanooga, Tennessee. This historic site protects a bubble of limestone glade and xeric limestone prairie habitat in an otherwise heavily developed, urban area. A floristic survey was conducted across two growing seasons, yielding 212 taxa across 152 genera and 58 families. Seventy-four non-native taxa were documented, about 35% of the total flora. Six rare, state-ranked species were documented: Baptisia aberrans, Clematis fremontii, Hypericum dolabriforme, Packera paupercula var. appalachiana, Symphyotrichum ericoides var. ericoides, and Viola egglestonii. An exploration of Civil War-era herbarium specimens and historical documents illuminated the historical flora of the site, and through the geolocation of herbarium specimens of select “indicator species,” the authors demonstrated that grassland habitats were once more abundant in the Chattanooga area.

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The Demography of Gentiana autumnalis in Populations Under Varying Management Regimes in New Jersey

ABSTRACT: Gentiana autumnalis (pine barren gentian) is a rare, fall-flowering perennial that is endemic to pine barren habitat from New Jersey to South Carolina. This disturbance-adapted, early successional species is at risk in New Jersey as a result of human interactions, namely growing season mowing and fire suppression. We used a repeated measures design to compare the differences between managed (mowing and prescribed fire) and unmanaged G. autumnalis populations for density, life stage, mortality, and fecundity. Managed populations had a greater gentian density, proportion of reproductive individuals, and seedlings compared to unmanaged populations. Implementing prescribed burns and mowing at previously unmanaged sites prior to spring growth increased gentian density, flowering, and seed set the same year. Our data support that prescribed burning and mowing can be beneficial management tools for the conservation of G. autumnalis and other disturbanceadapted species that require open early-successional habitat. However, their implementation can have negative consequences if conducted during the growing season, especially for roadside populations that are periodically mowed. Declining rare plant populations have the potential to benefit from management practices that facilitate ideal growing conditions and influence life stage transitions that will best improve population growth rate over time

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Scientific Note: Facultative Perenniality in the Dwarf Sundew (Drosera brevifolia)

ABSTRACT: The dwarf sundew (Drosera brevifolia) occurs from Uruguay to Virginia. Disjunct populations occur in the southeastern U.S. with the northernmost in Kentucky. Despite this wide distribution, relatively little is known about the biology of this species. It has been described as both annual and biennial. The endangered Kentucky population is considered biennial, but occasionally, live, mature plants have dead flower stalks in early autumn suggesting some may be perennial. In 2013, 40 sundews that germinated in the fall of 2012 were marked as they flowered in 2013. They were observed into a third growing season in 2014 until the end of July. Sixteen plants (40%) died after setting seeds in their second growing season, while nine (22.5%) remained alive, flowered, and set seeds again the following year. Seven of these were still alive at the end of July 2014. Fifteen plants were puzzling as the leaves were dead after setting seeds in their second growing season, but were alive May 2014, of which 12 flowered. This study confirms that at least a portion of the Kentucky population of D. brevifolia is perennial. This is probably facultative perenniality because some plants only survive to a third growing season when precipitation falls evenly over the growing seasons and when no hot, dry periods occur. Mild winters without extensive snow cover may contribute to facultative perenniality as well

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Phenotypic Variation in Climate-Associated Traits of Red Spruce (Picea rubens Sarg.) along Elevation Gradients in the Southern Appalachian Mountains

Red spruce (Picea rubens) is a long-lived tree species that thrives in cool, moist environs. Its ability to adapt to rapidly changing climate is uncertain. In the southern Appalachian Mountains, red spruce reaches its greatest abundance at high elevations, but can also occur across a range of mid and lower elevations, suggesting the possibility of a correlation between genetic variation and habitat. To assess clinal phenotypic variation in functional traits related to climate adaptation, we collected seed from 82 maternal sib families located along replicated elevational gradients in the Great Smoky Mountains National Park, TN (GSMNP) and Mount Mitchell State Park, NC (MMSP). The percentage of filled seeds and seed mass increased with elevation, indicating that successful pollination and seed development was greatest at the highest elevations. Seedlings sourced from GSMNP displayed a strong relationship between elevation and bud set when grown under common garden conditions. High elevation families set bud as many as 10 days earlier than low elevation families, indicating adaptation to local climate. Across parks, no effect of elevation was noted for bud flush. Our results demonstrate that red spruce in the southern Appalachian Mountains displays clinal variation in bud set that may reflect local adaptation to climate, although this varied between the two parks sampled. We suggest that genetic adaption of red spruce to different climate regimes, at both local and broad spatial scales, is in need of more intensive study, and should be carefully considered when selecting seed sources for restoration.

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Noteworthy Collections: An Overlooked Specimen of Conyza ramosissima from Virginia

Conyza ramosissima Cronquist (ASTERACEAE) Page County: Rocky slope along road, 5 mi. NW of Luray, 20 June 1950, Bernard Mikula 5222 (FARM). Significance: This is the first report of Conyza ramosissima (syn. Erigeron divaricatus Michaux) from Virginia. The specimen collected by Mikula establishing this record was encountered in the course of a study of herbarium material of C. canadensis (L.) Cronquist to distinguish its varieties [var. canadensis and var. pusilla (Nuttall) Cronquist] as they occur in Virginia; Mikula’s specimen had been initially identified as Erigeron canadensis L. Conyza ramosissima is best distinguished from other species in the genus by its profusely branched habit, generally lacking a well-defined main stem, its relatively low stature, usually ranging 1–3 dm tall, and strigose stem pubescence (Fernald 1950; Strother 2006). It also has distinctive white-margined phyllaries that lack the characteristic green tips found in C. canadensis var. canadensis or the red to purple tips typical of var. pusilla. In all respects, Mikula 5222 matches typical Conyza ramosissima. Examination of Conyza from FARM, GMUF, JMU, LFCC, LYN, ODU, URV, VPI, and WILLI failed to reveal any other specimen of Conyza ramosissima from Virginia, nor are specimens of this species held at the Shenandoah University herbarium (Woodward Bousquet, pers. com.). While geographic data for Mikula’s specimen are somewhat vague, the fact that Massanutten Mountain and the George Washington National Forest dominate the landscape northwest of Luray, Virginia, limits the likely locations for his roadside collection. Searches in the vicinity of all accessible pullouts on Rt. 675 on the mountain failed to reveal any trace of this plant on June 19–20, 2019. Distribution maps from the Biota of North America Program (BONAP) (Kartesz 2018) show C. ramosissima to occur widely in North America between, roughly, the 85th and 110th meridians; it appears to be most frequent in Kansas and Missouri. Notably, Conyza ramosissima was documented once in the late 19th C, presumably as a weed, from the Japanese Gardens, Fairmont Park, Philadelphia, Pennsylvania: Isaac Burk s.n., without collection date (PH). The Page County, Virginia, station reported here is at least 300 miles east of the nearest documented native occurrence on the BONAP map. The ruderal roadside habitat of this one known Virginia specimen is consistent with the weedy characteristic of the species and suggests that the status of waif is appropriate for this species in Virginia.

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Germination, Survival, and Establishment of a Rare Riparian Species Alnus maritima

Abstract: Seed mortality due to low winter temperatures has been proposed as an explanation for the lack of seedling recruitment in natural populations of the rare riparian species Alnus maritima, but other factors such as the absence of essential root symbionts or canopy clearing disturbances could also limit establishment of new individuals. We investigated whether any of these factors could be identified as preventing recruitment into existing seaside alder populations. Stratification studies showed that not only can seeds withstand low temperatures, longer periods of cold stratification promote earlier seed germination and expand the temperature range for germination. Root microbiome studies unexpectedly found that seedlings inoculated with the native microbiome prior to planting had lower survival compared to uninoculated individuals, and uninoculated individuals declined in survivorship after natural inoculation in the field. Canopy disturbance by burning or clipping vegetation promoted neither seedling growth nor survival initially, with seedling survival lower in burned plots due to the release of an aggressively growing competitor. Our results show that physiological stress by microbial symbionts and competition with other species are likely primary limiting factors—more so than seed mortality from low temperatures—and should be the focus of future conservation efforts.

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Germination Traits in the Threatened Southeastern Grassland Endemic, Marshallia mohrii (Asteraceae)

Marshallia mohrii (Asteraceae) is a perennial forb endemic to grasslands in the southeastern United States. Despite having been listed as federally threatened for three decades, little is known about its biology and life history. In this study, we examined the role of light, temperature, seed age, and cold stratification on seed dormancy break and germination in M. mohrii. We also quantified soil temperatures in a Ketona glade population of M. mohrii to infer dormancy breaking and germination phenologies under natural conditions. Relatively high proportions (>65%) of cold stratified seeds germinated across a range of temperature regimes in both light and darkness, whereas nonstratified seeds only germinated to high proportions in light at high temperatures. Germination proportions of laboratory stored seeds were slightly greater than freshly matured seeds, but remained much lower than those of cold stratified seeds. According to laboratory experiments, both autumn and spring germination phenologies are possible depending on the temperature and light conditions seeds experience after dispersal. Seeds of M. mohrii exhibited type 3 non-deep conditional physiological dormancy, which has been found in other members of Asteraceae from temperate grasslands. Overall, the germination niche of M. mohrii is defined by conditional seed dormancy, reduced dormancy levels following cold stratification, dark germination after dormancy loss, seasonal germination cueing, and seed traits consistent with short-term persistence in soil. Results from our study are useful for future conservation and recovery actions with M. mohrii and represent the first known published report of germination traits in this genus, which contains several other rare and rangerestricted species.

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Aquatic Vegetation of Springs at Buffalo National River, Arkansas

ABSTRACT: The biodiversity of freshwater springs in the Arkansas Ozarks is poorly described and has received relatively little attention from researchers. Information on the biodiversity of springs is crucial for their management and conservation. This study describes the aquatic and semi-aquatic plant communities and key habitat features of several springs located at Buffalo National River, Arkansas. We report 58 taxa from among all springs, including eight genera of algae, one species of horsetail, three marchantiophytes, and one bryophyte. Among angiosperms, we found 21 species of monocots and 24 species of eudicots. Six non-native species occur among the springs and none are considered to be invasive. Data show that impounded springs tend to have higher plant diversity than springs with primarily lotic geomorphologies. Cluster analysis showed that the springs with a prominent lentic structure were most similar to each other with respect to shared taxa, while the springs with well defined, long spring-runs and no functional impoundments shared the most taxa. Geographic proximity in the watershed does not appear to play a substantial role in similarity of plant populations, indicating other factors are involved. An NMDS analysis of habitat and water chemistry data corroborated the cluster analysis and showed that habit structure plays a key role in plant community composition. Springs at Buffalo National River occurring within the Boston Mountains and Springfield Plateau appear to have lower taxonomic diversity compared to the larger springs occurring on the adjacent Salem Plateau, which is likely because of their low magnesium concentrations.

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An Assessment of the Vulnerability of Illinois’ Rarest Plant Species to Climate Change

Illinois is home to approximately 2,107 native plant species of which about 16% are listed as threatened or endangered (T & E). In addition to the common threats associated with the decline of these species, climate change is a rapidly emerging threat. Climate predictions for Illinois have estimated that summer temperatures will resemble present-day summers in Texas by mid- to latecentury, while precipitation patterns are less predictable. Using NatureServe’s Climate Change Vulnerability Index (CCVI) tool we evaluated the climate change vulnerability for all 331 of Illinois T & E plant species. Overall, we found that over 80% are vulnerable to climate change. Barriers to migration are a leading factor associated with vulnerability in Illinois, where 97% of listed species are affected by anthropogenic barriers and 24% are affected by natural barriers. The sensitivity of species to changes in temperature, precipitation, and hydrology are also associated with vulnerability. The CCVI score was associated with most of the dozen or so other factors incorporated in the tool, though to a lesser degree. This study provides insights into the most vulnerable plant species in Illinois and provides much needed information to land managers, policy makers, and researchers. By highlighting which T & E species are most vulnerable to climate change, and what factors are most responsible for their vulnerability, this work will aid in prioritizing limited resources and developing adaptation strategies for them.

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