Current Issue
Volume 88 — Issue 2 (Dec 2023)

A Novel Anatomical Approach to Complement Morphological and Ecological Methods for the Identification of Some Important Coastal Graminoids

We present anatomical imaging techniques and measurements that are useful additions to the existing morphological toolbox for the identification of seven coastal grasses and one rush. Our method is simple and inexpensive and requires the removal of only one leaf, which prevents removal of plants from their habitats. This method can also be used in seasons when reproductive structures (important for current morphological ID efforts) are not present. We find significant quantitative differences in leaf width, adaxial to abaxial ratios (ADAB ratio, which we introduce as a new parameter), vascular bundle cross-sectional areas, and interveinal distances, as well as providing images for qualitative analysis of these plants’ anatomies; including differences in bundle sheath structures, fiber distributions, epidermal and cuticular properties, and chloroplast positioning.

Scientific Note: Revisions in a Collection of Plant Fossils from the Middle Pennsylvanian Age Mazon Creek Locality (Illinois) at the North Carolina Museum of Natural Sciences

We evaluated an assemblage of 235 plant fossil specimens from the well-known Middle Pennsylvanian Mazon Creek locality accessioned into the Paleontology Collections of the North Carolina Museum of Natural Sciences (Raleigh). The specimens are preserved as siderite nodules, common to the Mazon Creek biota. All but three of the specimens were donated by Mr. George Oliver, and were found at a quarry near Joliet in Will County, Illinois. The collection includes pteridosperms, pteridophytes, lycophytes, equisetophytes, cordaites, and specimens of unknown affinities, and includes relatively rare specimens of Codonotheca caudua and Cordaianthus ovata. Forty-four previously unidentified specimens were identified to genus or species. Sixty specimens were previously misidentified and corrections were made. This is a small but noteworthy collection that increases paleobotanical material available for researchers to access.

Noteworthy Collections: First Record of a Natural Hybrid Between Phlox divaricata ssp. laphamii (Alph. Wood) Wherry and Phlox pilosa ssp. sangamonensis (Levin & D.M. Sm.)

Phlox pilosa ssp. sangamonensis is a state-endangered and narrowly endemic taxon only found in Champaign and Piatt counties, Illinois. Here, we present evidence of natural hybridization between Phlox divaricata ssp. laphamii and P. pilosa ssp. sangamonensis. In May 2018, we collected a putative F1 hybrid of the two taxa in a sympatric population. We screened six microsatellites developed for North American Phlox species and measured eight morphological traits to test the specimen’s hybrid status. The microsatellite data were analyzed using a Bayesian clustering technique to infer genetic groupings. The eight morphological characteristics were analyzed using principal components analysis. We also measured the flowering phenology of P. divaricata ssp. laphamii and P. pilosa ssp. sangamonensis to assess the possibility of cross pollination. Bayesian clustering and the principal components analysis indicated that the sample was a Phlox divaricata ssp. laphamii × Phlox pilosa ssp. sangamonensis. There was modest phenological overlap between the two taxa, suggesting that gene flow is possible—though likely uncommon—in sympatric populations. We then discuss the effects of this hybridization on P. pilosa ssp. sangamonensis conservation and genetic composition.

Developing a 3D Digitization Protocol at the Marshall University Herbarium Using Free, Open-source 3D Reconstruction Software

Herbarium specimen digitization and transcription initiatives have led to revitalized use of plant collections making them more accessible than ever. Most digitization is done by producing 2D images of herbarium sheets; however, herbaria also include 3D collections such as fungi, mosses, and dry fruits, among others. Here we present a 3D digitization protocol developed at the Marshall University Herbarium (MUHW) using free photogrammetry software. We tested four freely available software applications, Meshroom, 3DF Zephyr Free, ColMap, and Regard3D on five types of 3D specimens, fungi, a moss, a lichen, a pinecone, and a compound fruit. Using 40–50 images and equipment already available in our herbarium such as a camera and light box, we produced 3D images in less than one hour per specimen. From the four applications tested, 3DF Zephyr Free gave the best results across the different specimens. Specimens that are bilaterally symmetrical or asymmetrical, such as fungi and compound fruit yielded detailed 3D images. Radially symmetrical specimens or specimens with repetitive patterns, such as the pinecone, moss, and lichen, resulted in poor or incomplete 3D images, which indicates that this workflow may be best suited for objects with differentiation in surfaces. Our workflow provides an effective, low-cost method of producing 3D images of 3D herbarium specimens that can be easily implemented in other herbaria.

Scientific Note: Neotypification of Ptelea mollis M.A. Curtis (Rutaceae)

Ptelea trifoliata L. (Rutaceae), in the sense of Bailey (1962) and Skornia et al. (2016), is a woody, understory species native to the southeastern and midwestern regions of the United States, as well as Mexico. It is one of two species initially described in Ptelea L. by Linnaeus (1753), the other being Ptelea viscosa L. [Dodonaea viscosa (L.) Jacq., Flora of China Editorial Committee 2007]. The circumscription of Ptelea in North America has been controversial, with authors variously recognizing a single species (Linnaeus 1753), three species (Bailey 1962), or 59 species (Greene 1906). Those adopting broader species circumscriptions, and thus fewer species, have variously recognized a number of subspecies and varieties within P. trifoliata (e.g., Bailey 1962: 5 ssp./10 var.; Skornia et al. 2016: 5 ssp./7 var.). Differences in taxonomic concepts are primarily the result of morphological heterogeneity and lack of understanding of genetic relationships in the group. Without a deeper understanding of the latter, circumscriptions are likely to continue to flux and remain unresolved. Typification of published names is critical to any effort to resolve taxonomic issues. We seek here to contribute to filling this gap, by addressing the typification of a name proposed by Reverend M.A. Curtis: Ptelea mollis M.A. Curtis (1849).