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Ireland, being an island situated on Europe's western seaboard, has a fewer number of native species than mainland European Union Member States (MS). Increased numbers of vectors and pathways have reduced the island's biotic isolation, increasing the risk of new introductions and their associated impacts on native biodiversity. It is likely that these risks are greater here than they are in continental MSs, where the native biodiversity is richer. A horizon scanning approach was used to identify the most likely invasive alien species (IAS) (with the potential to impact biodiversity) to arrive on the island of Ireland within the next ten years. To achieve this, we used a consensus-based approach, whereby expert opinion and discussion groups were utilised to establish and rank a list of 40 species of the most likely terrestrial, freshwater and marine IAS to arrive on the island of Ireland within the decade 2017-2027. The list of 40 included 18 freshwater, 15 terrestrial and seven marine IAS. Crustacean species (freshwater and marine) were taxonomically dominant (11 out of 40); this reflects their multiple pathways of introduction, their ability to act as ecosystem engineers and their resulting high impacts on biodiversity. Freshwater species dominated the top ten IAS (seven species out of ten), with the signal crayfish (Pacifastacus leniusculus) highlighted as the most likely species to arrive and establish in freshwaters, while roe deer (Capreolus capreolus) (second) and the warm-water barnacle (Hesperibalanus fallax) (fifth), were the most likely terrestrial and marine invaders. This evidence-based list provides important information to the relevant statutory agencies in both the Republic of Ireland and Northern Ireland to prioritise the prevention of the most likely invaders and aid in compliance with legislation, in particular the EU Regulation on Invasive Alien Species (EU 1143/2014). Targeted biosecurity in both jurisdictions is urgently required in order to manage the pathways and vectors of arrival, and is vital to maintaining native biodiversity on the island of Ireland.

As part of ongoing efforts to understand, document, and conserve the flora of southeastern North America, we propose two new species, the recognition of a usually synonymized variety, the acceptance of two species of Waltheria as being present in peninsular Florida, taxonomic acceptance of a sometimes deprecated species transferred with a new name into a different genus, and we clarify the distribution and ecology of a species. In Carex (Cyperaceae), we re-analyze infrataxa in Carex intumescens and recommend the recognition of two varieties, a taxonomic schema first proposed in 1893, but usually not followed in the 128 years since. In Euphorbia (Euphorbiaceae), a careful assessment of south Florida material of Euphorbia subg. Chamaesyce sect. Anisophyllum subsect. Hypericifoliae reveals the need for taxonomic changes to best classify endemic representatives of this group, resulting in the naming of a new species, and a new name at species rank in Euphorbia for a taxon first named in Chamaesyce and sometimes subsequently treated at only varietal rank in Euphorbia. Chamaecrista deeringiana (Fabaceae, subfamily Caesalpinioideae) has been repeatedly misinterpreted to include two different and disjunct population systems with differing morphologies and habitats, which are here interpreted as separate species, one newly named and the other Chamaecrista deeringiana returned to its original and narrower interpretation as a south Florida endemic. Waltheria (Malvaceae) has sometimes been interpreted as being represented in Florida by a single taxon, Waltheria indica, but we disentangle the concepts of the widespread W. indica and the West Indian W. bahamensis and clarify that both are present in the southeastern United States. We reconsider the occurrence and habitat of Toxicoscordion nuttallii (Melanthiaceae) in three states in which it has been reported as a rare species, Mississippi, Missouri, and Louisiana, and remove it from the Mississippi flora as a garbled and false report. In Louisiana, its occurrence in calcareous prairie complexes limits its potential occurrence in the state to a specialized and rare habitat, but careful exploration of habitat remnants may result in the discovery of additional populations. Taxonomic studies and re-assessments of this kind are critical in laying the best scientific foundation for regulatory, policy, and land conservation decisions. This paper names or makes the case for the renewed acceptance of six species with range-wide conservation concern: one Critically Imperiled (G1 – Euphorbia ogdenii), one Imperiled (G2 – E. hammeri), and four Vulnerable (G3 – E. garberi, E. porteriana, Chamaecrista deeringiana, C. horizontalis).

As part of ongoing efforts to understand, document, and conserve the flora of southeastern North America, we propose a number of taxonomic changes, nomenclatural changes, interpretations of nativity, and distributional accounts. Regarding the Asaroideae (Aristolochiaceae), we support continued recognition of Hexastylis (and other segregates of a very broad Asarum s.l.) at generic rank and make the necessary combinations to continue the use of Hexastylis in southeastern North America floras. In Conoclinium (Asteraceae), we present morphological and distributional evidence corroborating the recent suggestion (based on molecular evidence) that Chapman’s 1878 C. dichotomum is distinct, warrants recognition, and is present as a second Conoclinium in the southeastern North American flora. An analysis of historical accounts of Gaillardia pulchella (Asteraceae) strongly suggests that its modern occurrence east of Texas is adventive, rather than native. Two rare southeastern United States skullcaps, Scutellaria mellichampii and S. ocmulgee (Lamiaceae), have been persistently confused with one another and other species; we present a reassessment of the taxonomic distinction between them, best ways to distinguish them and similar species, and their known distributions. A reassessment of the taxonomy, distribution, and ecology of Linum carteri (Linaceae), a rare southern Florida endemic, confirms that two species should be recognized by modern species concepts; we make the necessary new combination to effect the recognition of two narrowly endemic species. In Andropogon (Poaceae), we propose that A. virginicus var. decipiens warrants recognition as distinct at species rank from other entities in the Andropogon virginicus complex. We also present more comprehensive information on the distributions of four species of “bushy bluestems” (Andropogon glomeratus s.l.), their ecology, and their practical recognition. In the Violaceae, modern reassessment of the taxonomy of many species (especially in the genus Viola) by H.E. Ballard, Jr. and collaborators have been vexed by uncertain application of many “old” names; we here provide a first installment of typifications and nomenclatural interpretations needed to move forward with a modern treatment of the genus in our region. In Xyris (Xyridaceae), we re-establish the generally ignored X. elliottii var. stenotera based on careful and extensive study of its morphology and ecology in comparison to X. elliottii var. elliottii, including a transplant study. English naturalist Mark Catesby (1683–1749) has been honored by having a genus and fifteen species of plants named for him, but most of these honorific names have been constructed in manners contrary to the Shenzhen Code; as these are “errors to be corrected,” we therefore propose to correct and standardize these honorifics by restoring his name ‘catesby-‘ as the root of the names. Similarly, in seven names (variably formed) employed by W.W Ashe to honor his cousin and (later) wife Margaret Haywood Henry (Wilcox) (Ashe), we also standardize and correct the root of the names to be accurately based on her name, ‘margaret-,’ in conformance with the Shenzhen Code.

Successfully reintroducing rare plant populations to recover historical community composition may require multiple efforts and greater lengths of time than is typically devoted by researchers. To improve the probability of successful colonization and to learn about the life history of the regionally endangered mahogany mistletoe (Phoradendron rubrum) in the Florida Keys, United States, we conducted sequential augmentations for 10 years across two host tree sizes, two seed sources, and six recipient sites. Long‐term monitoring for 13 years revealed that sowing fresh seeds in dry periods from introduced versus wild plants onto small diameter trees (<20 cm diameter at breast height [dbh]) that had branch diameters 15–20 mm resulted in the greatest colonization success. An average of 38.7% of seeds germinated and 23.8% survived to 2015. Plant development was quite slow. Seeds required over 100 days to germinate, 1.6 years for cotyledon emergence, and over 4.7 years to produce fruit. We detected first recruitment nearly 8 years after installation. Population growth improved following multiple attempts and expanded spatial extent as is predicted by theory. Portions of the life cycle are undetectable and thus could give false indications of reintroduction success or failure. Achieving and documenting unequivocal success of this reintroduction has required over a decade.

This datasheet on Lygodium japonicum covers Identity, Overview, Distribution, Dispersal, Hosts/Species Affected, Diagnosis, Biology & Ecology, Environmental Requirements, Natural Enemies, Impacts, Uses, Prevention/Control, Further Information.

This datasheet on Portulaca pilosa covers Identity, Overview, Distribution, Dispersal, Hosts/Species Affected, Diagnosis, Biology & Ecology, Environmental Requirements, Natural Enemies, Impacts, Uses, Prevention/Control, Further Information.