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The Scutellaria is a Labiatae genus (subfamily Scutellarioideae) with a highly specialised floral structure. The genus is characterised by a peculiar two-lobed calyx with a projecting appendage, named the scutellum. Here, we present a detailed analysis of floral development, using epi-illumination light microscopy, to clarify open questions about its floral organisation. Floral whorls appeared in an acropetal sequence, with a marked temporal overlap of petal and stamen appearance. Organ appearance in each whorl proceeded unidirectionally from the abaxial to the adaxial side. Significant developmental features included the formation of the scutellum, reduction of sepal lobes and formation of a three-lobed nectary disc. Our study revealed that both loss of organ initiation and fusion of primordia are responsible for the reduction in sepal members in Scutellaria. The nectary structure was markedly different from most other studied Lamiaceae.

Abstract. Noedoost F, Vaezi J, Nikzat Siahkolaee S. 2021. Taxonomic investigation of the Xanthium strumarium L. complex (Asteraceae) distributed in Iran inferred from morphological, palynological and molecular data. Biodiversitas 22: 1961-1974. Unclear species boundaries due to high morphological similarities lead to different opinions on Xanthium classification. To solve this problem, we conducted investigation on morphological, palynological and molecular (ITS sequencing) of three species of Xanthium (i.e., X. strumarium, X. sibiricum, and X. brasilicum) forming Xanthium strumarium complex in Iran. We randomly collected 110 plant individuals of the Xanthium strumarium complex as well as X. spinosum from 30 geographical populations in eight provinces of Iran. Pollen grains of 19 populations were studied by scanning electron microscope (SEM). Results obtained from the analysis of morphological characters showed that the three species, X. strumarium, X. brasilicum and X. sibiricum were placed nearly together specially X. strumarium and X. brasilicum are obviously overlapped. Palynological results indicated the pollen grains of section Acanthoxanthium (i.e., X. spinosum) and Xanthium (i.e., X. strumarium, X. sibiricum, and X. brasilicum) are clearly differing by their LM and SEM characters. However, no significant difference found between the pollen of X. strumarium and X. brasilicum. The Bayesian phylogenetic tree of the ITS region of rDNA sequences revealed that X. strumarium, X. sibiricum and X. brasilicum could not be discriminated as independent species. Overall, the morphological, palynological and molecular data provided evidence to synonymize X. brasilicum and X. strumarium with X. orientale and X. sibiricum with X. strumarium.

The genus Acer L. has about 156 species which are distributed in Asia, Europe, Northern Africa and North America. The species of Acer show extensive morphological and molecular diversity and the species that co-occur may hybridize; therefore, sometimes the species delimitation turns out to be difficult. Eight Acer (maple) species have been reported in Iran. The velvet maple—Acer velutinum Boiss (1846: 28)—is one of the largest maples in the world and the most frequent maple species in Iran. Morphologically speaking, two varieties have been cited for this species. Due to the extensive morphological variability, however, the researchers encounter difficulty delimiting these two varieties. Against this backdrop, the present study was performed with the aim to delimit two varieties of Acer velutinum by using both morphological and molecular approaches. It also aimed to proffer data on the genetic diversity of this species in the country. Nighty-four plant specimens of A. velutinum were randomly collected within 14 geographical populations at four provinces in Hyrcanian forests of Iran. The PsbA-trnHGUG intergenic spacer sequence of cp-DNA and the ISSR molecular markers along with the morphometric analysis and image analysis of the leaf shape were used. The numerical and phylogenetic analyses of the tree specimens from the presumed varieties of A. velutinum—based on morphology, image analysis of leaf shape, ISSR and cp-DNA—did not delimit these varieties; hence, A. velutinum was considered to have a high level of intergrading morphological variability. The population genetic study revealed significant molecular differences among the studied populations. The STRUCTURE plot and gene flow analysis (Nm), nevertheless, revealed some degree of shared alleles among the populations. The Mantel tests demonstrated significant correlation between the geographical and genetic distance of the studied populations; it further signaled the fact that the gene flow occurred mainly between the coterminous populations.