The floristic diversity and vegetation-environment relations in the southern part of the Eastern Desert, between 26°45′N and 24°1′N and between 32°45′E and 35°00′E and covering a total area of about 54,500 km 2 , were investigated. For this purpose, 142 georeferenced stands distributed in four transects were selected: 22 from Qena-Safaga road (T1), 28 from Idfu-Marsa Alam road (T2), 46 from Aswan-Kharit-Gimal (T3), and 46 from Red Sea Coastal Plain (T4). Altogether, 94 species belonging to 33 families were recorded, and the species richness (SR) varied from one transect to another: 46, 35, 52, and 46 in T1, T2, T3, and T4, respectively. Soil samples were collected from each stand, and the soil texture, soil moisture content, organic matter (OM), electric conductivity (EC), total soluble salts (TSS), pH, and major ions (Na + , K + , Ca +2 , Mg +2 , Cl-, SO 4-2 , and HCO 3-) were determined. The soil-vegetation relationships were assessed by both detrended correspondence analysis and canonical correspondence analysis. Both species diversity measurements (SR and H') exhibited significant differences among the separated vegetation groups within each transect. Classification of the vegetation resulted in 6, 7, 4, and 6 vegetation groups for T1, T2, T3, and T4, respectively. Canonical correspondence analysis showed well the relative positions of species and sites along the most important ecological gradients. The segregation of these groups along the first two axes of the biplot demonstrated that soil texture, moisture content, salinity, sulfates, and organic matter contents were highly correlated with the distribution of species.

The spore and pollen morphology of 15 species of Pteridophyta and Gymnospermae represented in the flora of Egypt is reported and described. These belong to four types: inaperturate (alete) with elaters (one species) and aperturate without elaters (14 species). The latter group comprises the monolete, trilete and polycolpate types. A key for the separation of the pollen types and genera is provided. The pollen morphology in relation to taxonomy is briefly discussed.

The flora and fauna of Arabia, particularly southern Yemen, has recently attracted the interest of many authors. In this study, the genus Heliotropium L. (Boraginaceae) is taxonomically revised in southern Yemen. Ten species are recognized. Nomenclature, typification, representative specimens and a diagnostic key to all species are provided, along with their distribution in southern Yemen. The taxonomically most valuable characters in the genus are those of flowers (calyx, corolla, androecium and gynoecium) and nutlets, and those characters are thoroughly investigated and discussed. Both light and scanning microscopy are used in the investigation. Papillate anther apices (brush-like) were recognized in some species. Connate anthers and deep or shallow ventral circular depressions on the nutlets were found to be useful in distinguishing members of H. sect. Orthostachys (viz. H. strigosum, H. rariflorum and H. ovalifolium), while winged nutlets were found only in H. pterocarpum. The length and hairiness of the style and stigma also proved to be taxonomically useful.

Introduction Boraginaceae Juss. s.l. is a very wide and diverse family; it was recently placed in the lamiid clade in APG IV (Angiosperm Phylogeny Group, 2016). The delimitation of Boraginaceae Juss. s.l. is problematic since the family concept is too broad. On the basis of floral and nutlets/seeds characters, Gürke (1893) recognized four subfamilies:

Pollen grains of 20 species belonging to 7 genera of Polygonaceae represented in the Flora were studied using Light and Scanning Electron Microscope. Pollen characters, including those of size, shape, exine sculpture and structure of the aperture allowed the recognition of five pollen types: Atraphaxixs, Calligonum-Oxygonum, Persicaria, Polygonum and Rumex-Emex types. A key for the seperation of the different types is provided and the pollen morphology in relation to taxonomy of the investigated taxa is briefly discussed.