For the first time, an updated checklist of Acacia, Senegalia and Vachellia species in Egypt is provided, focusing on the exotic species. Taking into consideration the retypification of genus Acacia ratified at the Melbourne International Botanical Congress (IBC, 2011), a process of reclassification has taken place worldwide in recent years. The review of Acacia and its segregates in Egypt became necessary in light of the available information cited in classical works during the last century. In Egypt, various taxa formerly placed in Acacia s.l., have been transferred to Acacia s.s., Acaciella, Senegalia, Parasenegalia and Vachellia. The present study is a contribution towards clarifying the nomenclatural status of all recorded species of Acacia and its segregate genera. This study recorded 144 taxa (125 species and 19 infraspecific taxa). Only 14 taxa (four species and 10 infraspecific taxa) are indigenous to Egypt (included now under Senegalia and Vachellia). The other 130 taxa had been introduced to Egypt during the last century. Out of the 130 taxa, 79 taxa have been recorded in literature. The focus of this study is the remaining 51 exotic taxa that have been traced as living species in Egyptian gardens or as herbarium specimens in Egyptian herbaria. The studied exotic taxa are accommodated under Acacia s.s. (24 taxa), Senegalia (14 taxa) and Vachellia (13 taxa). Identification keys for the studied genera, generic groups and species have been provided using different taxonomic criteria. For each taxon, the validated name with the first citation followed by relevant Egyptian citations, typification, synonyms, distinctive features, origin, ecology (when available), utilisation and selected specimens are provided. The study revealed the presence of 22 newly recorded taxa in Egypt. Additionally, a list of excluded, unvalidated and unresolved names is given.

Allium (Amaryllidaceae) is diverse and taxonomically problematic, with controversial subdivisions and polymorphic species. In Egypt, the genus has not been investigated satisfactorily in terms of palynology. The present study aims to provide palynological information on the endemic and near-endemic species for the first time in Egypt and to characterize the investigated taxa's pollen diversity. Pollen morphology of twenty-one Allium taxa was studied comprehensively by scanning electron microscopy. Twenty-five traits were surveyed, then subjected to Hierarchical Cluster Analysis (HCA) and Principal Coordinate Analysis (PCoA). Pollen grains are monads, heteropolar, monosulcate, or trisulcate, small to medium-sized (P = 10.44 − 29.76 μm, E = 18.97 − 59.24 μm), and the shape is peroblate or oblate. The sulcus may be anasulcate, meridionosulcate, or subzonasulcate. Sulcus ends are blunt, pointed, rounded, or undulated. The exine ornamentation is variable and diversified between the distal pole and the equator. The current study highlighted the importance of pollen characteristics such as pollen size parameters, pollen shape, aperture type, polar outline, sulcus size parameters, sulcus type and end shape, distance between sulcus ends, exine ornamentation, presence or absence of perforations on the exine, and perforations size and density for the discrimination among Allium taxa in Egypt. The HCA confirms that pollen morphology has limited taxonomic usefulness at the sectional level for the studied taxa. While the PCoA results were more informative to visualize the infrageneric classification based on the studied palynological traits. A dichotomous identification key of twenty-one Allium taxa in Egypt based on palynological data is presented.

Eleven Terminalia species growing in streets and gardens in Cairo (Egypt) were investigated for their pollen morphology. The study's objectives were to explore the variation among Terminalia species' pollen pheno-characters and to categorize the various species within this genus according to these pollen characteristics. The results showed that there are significant variations in the pollen morphological characteristics in the genus under study, and as a result, these traits can be regarded as eurypalynous. Each of the two main categories of Terminalia species - mono-morphic and di-morphic - includes various pollen morphologies, ranging from spheroidal to prolate with hexa-aperture that may be similar or of two types. For each of the eleven species, an identification key and a clustering phenogram for the fifteen major pollen features have been created. The aperture type, aperture similarity, and exine ornamentation are some of the crucial traits for the differentiation of the species examined while the pollen shape class has a poor diagnostic character. According to the unique characteristics of the pollen morphology of the Terminalia species, three groups and two subgroups were identified.

Trichomes are extensions of the epidermis, frequently used as diagnostic traits for determining plant species. Solanum L., 1753 is a widespread and taxonomically complex genus. Although the genus Solanum has been the subject of numerous types of research, little attention has been given to the trichomes of the wild species found in Egypt. Therefore, the objective of the current study was to examine trichome types in ten wild Solanum species and assess their taxonomic importance. Using light, scanning electron microscopy and line drawings, indumentum characteristics on the abaxial leaf surface are investigated. The results showed a wide range of variation in trichome density on a 1 mm2 area of leaf blade (sparse, moderate, and dense), nature (glandular or non-glandular, simple or stellate), and structure (number of composing cells in simple non-glandular and glandular stalk and head; the number of radiating rays in stellate hairs). SEM revealed the existence of unique wax structures, including warty granules in addition to flakes. Our observations are consistent with the general characteristics of the subgenus Leptostemonum and the subgenus Solanum. This work provides strong evidence for the separation and interspecific delimitation of the investigated Solanum species using trichome morphology as a significant taxonomic trait.

Morphological, anatomical, and molecular information facilitates the identification and inference of the relatedness of plant species. In this study, the macromorphological, micromorphological, and anatomical characteristics of nine species from the Brachychiton and Sterculia genera belonging to the Malvaceae family were examined by light and a scanning electron microscope. The study recorded 66 macromorphological, micromorphological, and anatomical characteristics, thus revealing important variations between the studied species in leaf morphology and anatomy. This included variations in leaf complexity, leaf arrangement (phyllotaxy), epidermal cell walls, and their sculpture, as well as in the types of glandular and non-glandular trichomes. The studied species were mostly conserved in shedding patterns, being evergreen only in one out of nine studied species. Similarly, eight species were petiolate. Conversely, leaf arrangement and leaf complexity characteristics were highly divergent among the studied species, though only one species, Sterculia foetida, had compound leaves. The differences in the studied features and the chloroplast genes MaturaseK (MatK) and ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcl) were exploited to deduce the relationship between the studied species. While the morphological and anatomical features demonstrated a close relationship between the studied intrageneric species, the DNA barcoding analysis proved very efficient in distinguishing the two neighboring genera. Collectively, the different clustering analyses suggest a close relatedness between Brachychiton acerifolius and B. australis, while only DNA-based clustering demonstrates cladistic monophyly of the Sterculia species. This study, therefore, provides a detailed description of various morphological and anatomical features important for the systematic studies within the Malvaceae family and highlights the value of incorporating morphological, anatomical, and molecular approaches for inferring the evolutionary relationship between closely related plant species.

Pollen grains of the five cultivated species of Pinus L., 1753 from Subsect. Pinaster (Order Pinales, Family Pinaceae) were collected from the Orman Botanic Gardens at Giza in addition to the herbarium specimens. They were examined by light and scanning electron microscopy to detect the taxonomic value of their pollen characteristics. The pollen grains were bisaccate. An artificial key constructed according to the morphology of pollen grains recognizes the five species that belong to Pinus: P. pinea Linnaeus, 1753; P. canariensis Smith, 1828; P. halepensis Miller, 1768; P. roxburghii Sargent, 1897; and P. brutia Tenore, 1811. The differential items included the presence or absence of apertures, e.g. the monosulcate colpus that presents in P. pinea and P. brutia; pollen shape without sacci that could be perprolate as in P. pinea or prolate as in the remaining species; pollen shape (outlined with sacci) in polar view that could be haploxylonoid as in P. pinea and P. roxburghii or diploxylonoid as in the remaining species; in addition to cappa and sacci exine sculpture. A dendrogram from the Community Analysis Package statistical program for data analysis supported the separation of five species of Pinus in Egypt and showed that P. canariensis and P. halepensis were closely related, as well as P. brutia and P. roxburghii. The cluster separated P. pinea into a separate group, but it was more closely related to P. canariensis and P. halepensis. The cluster tree was illustrated, visualized, and confirmed by a heat map based on the R programming language for effective manipulation of the data.