Prosopis juliflora is one of the most problematic invasive trees in tropical and subtropical regions. Understanding driving forces affecting the potential global distribution would help in managing its current and future spread. The role of climate on the global spatial distribution of P. juliflora has been well studied, but little is known about the role of soil and human impacts as potential drivers. Here, we used maximum entropy (MaxEnt) for species distribution modelling to understand the role of climate (C), soil (S) and human impacts (H), C+S, and C+S+H in controlling the potential invasion range of P. juliflora, and to project its global potential invasive risk. We defined the top threatened global biomes, as predicted by the best-selected model. The incorporation of the edaphic factors improved the model performance and enhanced the accuracy of the outcome. Our findings revealed that the potential invasion risk increases with increases in mean temperature of the driest quarter (Bio9), soil alkalinity and clay fractions. Arid and semi-arid lands are at the highest risk of invasion than other moist biomes.

A taxonomic revision of the genus Amaranthus (Amaranthaceae) in Saudi Arabia, based on both field surveys and examination of harbarium specimens, is here presented. Collected exsiccata are kept the Herbaria PNUH and RO. An extensive literature was also analysed. Sixtheen non-hybrid taxa (twelve species) are recognized. Data about nomenclature (accepted names, main synonyms, and types), morphology, chromosome number, chorology (for native taxa) or alien status (for exotic taxa), occurrence in Saudi Arabia, ecology (preferential habitat, phenology, elevation), and taxonomic annotations are provided for each taxon. A diagnostic key is proposed. Four taxa (A. graecizans subsp. graecizans, A. graecizans subsp. sylvestris, A. graecizans subsp. thellungianus, and A. sparganicephalus) are native, whereas the other ones are to be considered aliens. A. dubius and A. blitoides var. blitoides are new for the national flora. Furthermore, the name A. sparganicephalus is neotypified on a specimen deposited at E and a nomenclatural change (A. blitum var. nanus comb. nov.) is proposed.

Sea beet (Beta vulgaris L. subsp. maritima (L.) Arcang.) is a wild member of the Amaranthaceae family and a progenitor for all the cultivated beets (Beta vulgaris subsp. vulgaris). It is a source of stress-resistant genes, contributing 21 valuable traits to sugar beet through multiple breeding approaches. Despite its importance, the core morphological diversity of sea beet within the Egyptian Mediterranean coastal region has not yet been thoroughly explored. The field observations indicated notable morphological diversity among sea beet populations. This study investigated the morphological diversity of six sea beet populations along with their associated soil and climatic conditions in their primary habitats. Our morphometric investigations identified two varieties: Beta vulgaris subsp. maritima var. glabra, characterized by glabrous, erect, larger basal leaves, and Beta vulgaris subsp. maritima var. pilosa, distinguished by its hairy, prostrate form with smaller basal leaves. These varieties exhibited differences in their spatial distribution, showing high variations at the inter- and intra-population levels as well as the variety level. Soil parameters significantly influenced population morphological variability, which demonstrated a strong positive correlation with soil organic carbon. Our results highlight the need for precise survey and molecular characterization to secure these potential genetic resources from alteration and loss, especially in coastal habitats that are particularly sensitive to future climate change.

The aims of the present study are to assess and update the floristic diversity of Amaranthaceae s.str. in Saudi Arabia. A total number of 33 taxa were indentified including 28 species, 4 subspecies, and 7 varieties. The richest genus is Amaranthus with 16 taxa (12 species); Aerva and Alternanthera have 3 species each; Achyranthes and Celosia 2 species each; 6 genera (Digera, Gomphrena, Nothosaerva, Psilotrichum, Pupalia, Saltia) include just one species each. Most of the taxa are native (18, 54.55%), 14 (42.42%) are aliens (6 casual taxa, 5 naturalized, and 1 invasive), one (Alternanthera sessilis) is here considered as doubtfully native, two (Amaranthus tricolor, Gomphrena globosa) are found only in cultivation. Two species (Amaranthus tortuosum, Pupalia lappacea var. lappacea) are excluded from the national flora. Diagnostic keys at genus, species, and infraspecific ranks are provided. The following names are lectotypified: Achyranthes argentea var. obovata (G; isolectotype at HBG), Achyranthes fruticosa var. pubescens (G), Achyranthes papposa (C; isolectotypes at C and BM), Achyranthes polystachya (BM), Aerva javanica var. bovei (FI), Achyranthes lanata (illustration by Burman), Digera arvensis (C; isolectotype at C), Psilostachys gnaphalobryum (TUB; isolectotypes at GOET, HBG, HEID, JE, MEL, MPU, P, and TUB), Telanthera bettzickiana (LE).

Several populations of Brassica tournefortii (Brassicaceae) occurring in Egypt are investigated from the micromorphological point of view (seed ornamentations). The species is known to show a notable phenotypic plasticity and five morphotypes was identified in the past. Furthermore, a soil analysis as well as a study of the fungal species from anthers were carried out. The aim of the study is to verify the taxonomic value of the morpholotypes of B. tournefortii and their ecologic relationship with soil variables. The results obtained demonstrated that the five morphological forms can be distinguished based on the seed sculpture. The Canonical Correspondence Analysis (CCA) exhibited a clear correlation between the soil variables and the identified forms. Six species of fungi were detected from the ecto-anthers in the Forms (F2-F4), while F1 was lacking the fungal species. The study revealed that the morphological plasticity of studied B. tournefortii depends on ecological factors.