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G. tenuis M. Bieb.) as regards leaves, seeds and pollens are presented with this investigation in a detailed way. An examination of the surface structure of the leaves, seeds and pollen grains of the Gladiolus species indicates that the characteristics of the ultrastructure of leaves and of pollen grains are not diagnostic for distinguishing species, but they could be important at genus level (leaves: features such as being amphistomatic, having the same quantity of immersed stomata on both surfaces and having a high stomata index, the presence and localisation of papillae, the shape of epidermal cells; pollen grains: monosulcate type with two operculums). However, the type of surface ultrastructure of the seed coat is a diagnostic feature as at genus level so for species. It can be mentioned that propose the use of features such as the shape and position of the cicatricle, the type of cuticle, the shape and boundaries of cells of testa, and the anticlinal cell walls as diagnostic features at genera level. The shape of seeds, the presence and disposition of wing, the level of the periclinal cell walls of the seed coat and types of relief are additional diagnostic features for distinguishing of Gladiolus species.

Climate and geography can influence biological soil crust (BSC) community composition, but local heterogeneity in variables such as soil characteristics or microclimate gradients can also impact cryptogamic diversity. Heavy metals and nutrient imbalances in serpentine soils are known to influence the distributions of higher plants, but cryptogamic species appear to be more tolerant of substrate. The aim of this study was to compare the cryptogamic composition of serpentine and non‐serpentine soils by using integrative taxonomy, which combines morphological and DNA barcoding data, to determine how soil characteristics in combination with rainfall can influence BSC community composition. Samples from serpentine and non‐serpentine soils were enumerated and total genomic DNA was isolated from the soil samples. Analyses of the 16S rRNA gene and ITS sequences were done using the quantitative insights into microbial ecology (QIIME) workflow to determine which eukaryotic microorganisms were present in the samples. Sixty genera from the Cyanophyceae (38), Chlorophyceae (10), Bacillariophyceae (6), Eustigmatophyceae (4), Trebouxiophyceae (1) and Xanthophyceae (1) classes were detected with this approach. Results confirm that algae and cyanobacteria are tolerant of most substrates and can even colonize environments with high levels of heavy metal and nutrient imbalances, if moisture is present. Genera such as Acaryochloris, Annamia, Brasilonema, Chrocosphaera, Halomicronema, Planktothricoides, Rubidibacter, and Toxopsis are reported for the first time for South African soil.

Despite a large body of work on the serpentine-substrate effect on vascular plants, little work has been undertaken to describe algal communities found on serpentine soils derived from peridotite and other ultramafic rocks. We report a preliminary study describing the occurrence of algae and cyanoprokaryotes on mafic and ultramafic substrates from South Africa. Results suggest that slope and aspect play a key role in species diversity and community composition and, although low pH, nutrients and metal content do not reduce species richness, these edaphic features also influence species composition. Further, typical soil genera such as Leptolyngbya, Microcoleus, Phormidium, Chlamydomonas, Chlorococcum and Hantzschia were found at most sites. Chroococcus sp., Scytonema ocellatum, Nostoc linckia, Chlorotetraedron sp., Hormotilopsis gelatinosa, Klebsormidium flaccidium, Pleurococcus sp. and Tetracystis elliptica were unique to one serpentine site. The preliminary survey provides directions for future research on the serpentine-substrate effect on algal and cyanoprokaryote diversity in South Africa.

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