The Plant Press

Staff Activities

From Plant Press, Vol. 28, No. 1, January 2025.

On November 25, Erika Gardner gave a presentation titled, “What is a Type Specimen,” to the Riderwood Senior Living Community Garden Club in Silver Spring, Maryland. The presentation included historical collecting accounts and the continued preservation of specimens, the use of DNA analysis of herbarium specimens to uncover new species to solve cryptic speciation issues, and how botanical illustrators use their skills to highlight characteristics of a plant to distinguish it from other similar species. 

Staff scientists and postdoctoral fellows from ForestGEO, including Stuart Davies, Eugenie Mas, Jose Medina, Krishna Anujan, Helene Muller-Landau, Luca Morreale, and Kelvin Acebron, attended the annual AGU (American Geophysical Union) conference in Washington, DC, on December 9-13. The conference is the “largest gathering of Earth and space scientists,” where individuals connect and share their research. The goal of the conference is to better understand the planet, environment, and how to address climate change. This year’s theme was “What’s Next for Science,” and it was attended by approximately 27,000 registered guests. ForesGEO post-doc Krishna Anujan presented a poster, “Sensitivity of tree growth to precipitation in seasonally dry tropical forests using long-term dendrometer band measurements”.

New Faces

From Plant Press, Vol. 28, No. 1, January 2025.

Danielle Remor (center) with Carol Kelloff and Warren Wagner

Danielle Remor is a Brazilian Ph.D. student in Botany at the State University of Feira de Santana (UEFS) and was awarded the 2024 Harold E. Robinson and Vicki A. Funk Award. Remor has been working with the Asteraceae family since her Master's degree. Her Ph.D. thesis aims to use integrative taxonomy to produce a phylogeny through phylogenomic methods for the genera Caatinganthus, Mattfeldanthus, Stilpnopappus, Strophopappus, and Xiphochaeta, which compose the Stilpnopappus alliance (Asteraceae, Vernonieae). Furthermore, she seeks to provide an updated taxonomic review and investigate, through biogeography, how these genera colonized the dry regions of Brazil. The U.S. National Herbarium houses a large number of collections of this group, including important Venezuelan specimens and type materials. During her one-month visit to the National Herbarium in October, supervised by Warren Wagner with assistance from Carol Kelloff, Remor was able to analyze and review the morphology of all morphotypes belonging to her study group, including relevant type specimens. The opportunity to visit the herbarium allowed her to access materials she had not yet been able to describe, significantly contributing to and expanding the results of her taxonomic review and updating the taxonomic identity of various materials. She also acquired samples from 10 species for DNA extraction, which will contribute to an overview of the taxonomic and evolutionary relationships of the genera in the Stilpnopappus alliance, providing valuable insights for the Vernonieae tribe.

Rose Villanueva (left) with Jun Wen, Tina Wang, and Yali Li.

Rosa María Villanueva Espinoza, a Master’s student in Botany at the South China Botanical Garden, was awarded a 2024 José Cuatrecasas Award. She visited the National Herbarium from October 7 through November 5, under the supervision of Jun Wen to study, “Taxonomy and phylogeny of the genus Justicia (Acanthaceae: Justicieae: Justiciinae) in Peru.” During her visit, Villanueva determined the species rank of various unidentified and misidentified Justicia specimens, some of which represent new taxa. In addition, she examined Justicia collections from other countries to help document the occurrence of Justicia boliviensis in Peru, constituting a new record for the country. Type collections and additional specimens from closely related species, such as J. inficiens, J. pilosa, J. lancifolia, and J. obovata, were revised. The revision of the US collection further elucidated the morphological similarities between J. wallnoeferi and J. cuscoensis. She also photographed diagnostic features such as stamens, seeds, and fruits of Peruvian species to enhance her Master's project. Furthermore, leaf fragments from 31 Justicia species were collected for future phylogenetic studies within this genus. Some of these findings, including new species and nomenclatural novelties, have already been included in a submitted manuscript to Phytokeys. A second paper, currently in progress, integrates the additional data obtained from the US and her revisions undertaken from various other herbaria.

Peanut illustration used to honor President Carter

From Plant Press, Vol. 28, No. 1, January 2025.

When Jimmy Carter (1924-2024) passed away on December 29, 2024, the Smithsonian's National Museum of Natural History used social media to honor him.

To mark his passing and to recognize that Carter rose from Georgia peanut farmer to the 39th president of the United States, the museum used an illustration of a peanut plant (Arachis hypogaea), which was drawn by Department of Botany illustrator Alice Tangerini.

The illustration was drawn in 1975 at the request of Edward Ayensu who included it in his article, “Africa in the American Presence,” a paper from the international conference The United States in the World held in 1976 in Washington, DC.

Illustration of a peanut plant (Arachis hypogaea) by Alice Tangerini.

Untangling Trebouxia, a green algal lichen photobiont in southern Africa

From Plant Press, Vol. 28, No. 1, January 2025.

By Ian Medeiros.

A recent study in the American Journal of Botany (2024; https://doi.org/10.1002/ajb2.16441) provides a first view of the southern African biodiversity of the green algal genus Trebouxia (Chlorophyta), the most common photosynthetic partner in lichens.

Trebouxia in a squash preparation of lichen thallus. Hale 78605 (US).

Southern Africa, particularly the Greater Cape Floristic Region, is a biodiversity hotspot for vascular plants and hosts a unique biota of lichen-forming fungi (mycobionts). However, the region’s lichen-forming algae (photobionts) had hardly been studied with molecular data or put into a global phylogenetic context. In the unicellular green alga Trebouxia, as with other lichen photobiont lineages, genomic variation far exceeds the limited morphological variation, and thus molecular data are essential for recognizing species.

To begin the process of applying a modern classification scheme to Trebouxia in South Africa and Namibia, an international team of scientists from the United States, Belgium, Chile, Hungary, Malaysia, Namibia, Panama, Poland, and South Africa sequenced the internal transcribed spacer (ITS) and rbcL from ca. 150 lichen thalli representing diverse mycobionts and biomes, from desert and fynbos to Afrotemperate forest and montane grassland. These sequences were incorporated into curated, global datasets; putative species were delimited with both phylogeny and operational taxonomic unit (OTU) clustering approaches as a way of ensuring that conclusions were robust to uncertain species boundaries.

We found that the Trebouxia biota of this region contains an estimated 43 species, representing 20–30% of global Trebouxia biodiversity. This is comparable to other well-sampled regions of the Southern Hemisphere (i.e., Bolivia and Kenya). On one hand, the results exemplify an “everything is everywhere” approach to microbial biogeography, with a majority of the southern African Trebouxia species shared with Bolivia, Kenya, or the Mediterranean basin. Conversely, seven species were only found in southern Africa, although further sampling will be required to assess whether they are truly southern African endemics.

Sampling for lichen photobionts in the northern mistbelt forest of the Buffelskloof Nature Reserve, South Africa. (photo by József Geml)

Patterns in species distribution and the mycobiont–photobiont association echoed what has been found elsewhere in the world. For example, the foggy Namib desert coast was dominated by species of Trebouxia clade A, something also seen in the Atacama Desert of Chile. The mycobiont genus Parmotrema was strictly associated with species from Trebouxia clade C, as has been observed in the Neotropics and Northern Hemisphere. Mean annual precipitation, but not mean annual temperature or precipitation seasonality, was found to have a significant effect on the composition of Trebouxia communities.

Only five of the species-level lineages recognized in this study have been formally described, highlighting the substantial Linnean shortfall in Trebouxia, but also providing a blueprint for future efforts to recollect, culture, and formally describe these species.