Volume 74 – Issue 3 (September 2009)

As awareness and interest in canebrake restoration activities in the southeastern United States continues to grow, we are faced with numerous challenges. The greatest of these challenges is obtaining enough germplasm to support restoration activities. Three propagation methods are reported in an effort to begin to elicit information regarding propagation of rivercane. Experiments to optimize micro-propagation, seed germination, and macropropagation methods were compared. Tissue culture (rapid clonal multiplication) has great potential for production of large numbers of propagules. Production of shoots has been optimized, using 4-6 mm diameter explants on MS media, containing 0.1 μM IBA (indole-3butyric acid ) and 0.01 μM TDZ (thidiazuron). However, the process is hampered by the current inability to generate roots. Maximizing seed germination offers the ability to exploit seed produced on existing canebrakes. Of the six temperature regimes tested on two populations, maximum germination occurred using roll towels, under a 35/25 or 30/20℃ temperature regime. Removal of lemma and palea from the seed increased germination percentage for one of the populations. Macropropagation from rhizome sections derived from stock maintained in pot-in-pot container production allowed for relatively easy harvest. Rhizome sections 2-3 nodes in length soaked for 60 minutes in warm water or 1000 ppm BAP (6-benzylaminopurine) showed greatest shooting yield. Individual mother plants have the potential to yield 400 viable clones. While each method had its apparent strengths, only the macro-propagation method showed immediate promise.

Arundinaria gigantea (Walt.) Muhl., commonly called river cane, is a member of the grass family (Poaceae). The primary purpose of this research is to characterize the physical and chemical properties of the soils of existing stands of A. gigantea in western North Carolina and to provide guidance for the restoration of river cane to the stream valleys of the Southern Appalachian Mountains. We analyzed soils at 20 sites in Cherokee, Jackson, and Macon Counties in North Carolina and collected data on soil characterization, nutrient levels, bulk density, particle size, pH, and hydraulic conductivity. River cane soils varied significantly for carbon, nitrogen, phosphorus, and sand levels, even within the same watershed (ANOVA, p < 0.05). Typical soils are very sandy, mineral soils with low carbon levels and low nutrient levels. Soils are well drained, have very low bulk densities, and low pH. Despite low nutrient conditions, the plant does not appear to be nutrient limited. Restoration potential for the species is high, but more research is required to determine specific limitations on growth.

The once dominant Arundinaria gigantea canebrake ecosystems have been reduced to fragmented populations less than 2% of their former extent resulting in a critically endangered ecosystem. Restoration of canebrakes is thus necessary for maintaining and enhancing biodiversity in the southeastern United States. Contemporary fragments of canebrakes are trapped between anthropogenic development and closedcanopy forests. The goal of this study was to assess the impact of light intensity on rivercane growth and physiology in both laboratory and field studies and thereby enhance restoration success. A laboratory experiment was conducted to test light (partial shading and no shading) and nitrogen(0,0.5,5.0,25, and 100g/L) effects on seedling growth. Potential interaction occurred between light and nitrogen. Levelsofnitrogenuptotentimesthecommerciallyrecommended amount(0.5g/L) significantly increased seedling growth when plants were grown under non-shaded conditions. A thinning site was established in an existing river cane population and forest canopy was reduced 60% by girdling overstory trees. Number of new shoots and new shoot diameter were both increased by thinning. In addition, light response curves demonstrated that rivercane had a typical C3 light response pattern and field readings showed that rivercane maintained net photosynthetic activity throughout the dormant season. Results indicate that rivercane growth is enhanced with increased light levels. Reductionofoverstory canopy is a potential management tool for enhancing survival and growth of existing populations.

Forest and grass riparian buffers are a common conservation practice to control nonpoint source pollution. In the lower midwestern United States, there is significant interest in incorporating a once common native riparian species, giant cane (Arundinaria gigantea) in riparian restoration designs. Thus, assessing the water quality benefits of giant cane buffers is warranted. Ground water nitrate and ammonium concentrations were measured at the field edge (0 m), and 1.5, 3.0, 6.0, 9.0, and 12.0 m from the field edge through giant cane and forest riparian buffers adjacent to agricultural fields along three streams in southern Illinois. Ground water nitrate and ammonium were not different between the giant cane and forest riparian buffers,nor were there significant reductions in these nutrients through the riparian zones when all three sites were considered. However, site-specific regressions of nutrient concentration vs. distance showed significant reductions (>80%) in nitrate through two forest and one cane riparian buffers, and a significant reduction in ammonium (95%) through a cane buffer. Our results indicate that buffer effectiveness may be dependent on landscape position and water table depth.

Arundinaria gigantea (river cane), a native bamboo species, was once abundant in river valleys of western North Carolina. Cane stands are now a rare ecosystem due to land use changes, but restoration efforts are underway. River cane reproduces mainly rhizomatously. Sexual reproduction is often characterized by gregarious flowering, followed by death of the flowering culms and possibly of the attached rhizomes. Suggestions have been made in the literature that clusters of flowering culms are monoclonal, but this has not been tested. In this study, leaves were sampled from sterile and fertile culms along transects from two stands in Jackson and Swain counties, North Carolina. Amplified fragment length polymorphism (AFLP) fragments were generated for these samples using three primer pairs. Most of the resulting AFLP fingerprints generated were not identical; however, using a threshold dissimilarity technique, we estimated the probable number of clones in our samples. The majority of fertile culms within a stand were determined to be monoclonal and distinct from some, but not all, of the sterile culms. Cluster analysis confirmed that most of the fertile culms within each stand were more genetically similar to one another than to the sterile culms, and that the two different stands had distinct sets of genotypes, with no genotype overlap between stands. On the basis of these findings, to maximize clonal diversity and minimize the impact of culm loss after flowering, restoration projects should use propagules collected from multiple stands and from multiple localities within a stand.

The drastic loss of giant cane (Arundinaria gigantea)-dominated communities (canebrakes) in southeastern North America has spurred great interest in habitat restoration. We report on two giant cane restoration studies that investigate the effects of collection source, rhizome propagule morphological characteristics and type (greenhouse-grown containerized stock plants or bare rhizomes), site, and time on genet survival and growth. Survival over the two studies (after three and five years) differed by propagule collection source, was marginally greater when planting older containerized stock, and varied between sites. Although field survival tended to be somewhat greater for greenhouse-grown containerized stock in comparison to bare rhizomes, overall survival was similar for both stock types when accounting for mortality of planted rhizomes in the greenhouse. The number of culms, their height, and spread of the genets increased over time and differed by planting stock type in each study. At Becca’s Tract, cane genet growth ranged from a mean of 1.4 ± 0.1 culms that were 41.7 ± 1.8 cm tall with essentially no spread after the first growing season to a mean of 80.6 ± 7.6 culms that were 99.8 ± 2.8 cm tall with a spread of 212.1 ± 19.6 cm after five years. Giant cane rhizome sections initially grown in a greenhouse or planted directly in the field can be used to establish canebrakes in a framework that is operationally feasible for large-scale restoration.

The Southern Appalachian Botanical Society annually presents the Elizabeth Ann Bartholomew Award in memory of Elizabeth Ann Bartholomew’s untiring service to the public, plant systematics and to SABS. At the 2009 meeting of the Society in Birmingham, Alabama, the Award was presented to Charlie Williams of Charlotte, North Carolina. The Award is presented to individuals for distinguished professional and public service that advances our knowledge and appreciation of the world of plants and their scientific, cultural and aesthetic values and/or exceptional service to the Society.

Arundinaria sensu stricto is a genus encompassing three species that are endemic to the Southeastern United States: A. appalachiana (hill cane), A. gigantea (river cane), and A. tecta (switch cane). The taxonomy of this group has been problematic due to a poor understanding of its phylogeny and genetic variation as well as ambiguity surrounding original protologues and designated nomenclatural type specimens. In particular, the neotype of Arundo gigantea (the basionym of Arundinaria gigantea) and the holotype of A. macrosperma (a synonym of A. gigantea) both provide insufficient morphological characters for species identification. Here we designate epitypes to assist with the correct application of the names of these taxa. A summary of diagnostic morphological features for the three species of Arundinaria and comments on their phylogenetic relationships based on recent molecular and morphological analyses are also provided.

Dr. Michael Woods, Professor of Botany and Curator at Troy University is the recipient of the 19th annual Richard and Minnie Windler Award. The Windler Award is presented annually for the best paper in plant systematics published in Castanea during the previous year. His paper, ‘‘The genera Desmodium and Hylodesmum (Fabaceae) in Alabama’’ was published in the March 2008 issue of Castanea 73(1):46–69.

I often describe the learning curve for algal taxonomy as an overhanging ice cliff, nearly unassailable to students who are unfamiliar with algal divisions and the peculiarities of dichotomous keys. Dillard’s introductory text, Common Freshwater Algae of the United States, provides a great introduction to algal taxonomy, with clear, simple choices that take students to eight sections separated by easily observed morphological differences (e.g., algae unicellular, alga not unicellular). Keys, illustrations, and ecological notes are provided for about 300 genera.