Achene Characteristics of Some Taxa of Asteraceae from the Northwestern Mediterranean Coast of Egypt

Abstract

Egyptian Journal of Botany http://ejbo.journals.ekb.eg/ Review 1 T HIS STUDY aimed to characterize the external morphology of achenes of the 74 taxa belonging to 51 genera and four subfamilies of Asteraceae from the Northwestern Mediterranean coast of Egypt. By using light microscopy, 26 quantitative and qualitative morphological characters were recorded. Among the studied taxa, achene symmetry, hairiness, surface topography, hilum position, presence or absence of pappus and pappus type were found significant diagnostic characters for delimiting the taxa. Two main groups were identified based on the presence or absence of hardened fruiting involucre. Four types and four subtypes were recognized: (1) Achene di-or trimorphic per capitulum, (2) Achene monomorphic and lacking pappus, (3) Achene monomorphic, with coroniform or auriculate pappus, (4) Achene monomorphic, with pappus. A description, photographs and identification keys were provided to assist in identification. Despite the taxonomic significance of achene exomorphology characters on the generic and specific level for the recognition of the different studied taxa of Asteraceae, no mutual link was shown between the taxonomic division of the family into subfamilies and tribes except for few cases.

Morphological Variation in Achenes in Certain Species Belonging to the Tribe Cardueae (Asteraceae) in Iraq

“…Out of the eight species, only Silybum marianum was found to have achenes that exhibited dimorphic or trimorphic, while the remaining species had achenes that were monomorphic. Interestingly, our findings concur with those of [12], [19], and [20]. The achene shapes in Silybum marianum and Carduus getulus were oblong; in Carthamus lanatus, Carthamus tinctorius, Carduus pyconocephalus, and Carthamus persicus, the forms of achene in Carthamus curdicus and Carthamus oxyacantha were oblong; but the species Notobasis syriaca was distinguished by an ellipsoid shape (Table 1 and Fig.…”

“…The identification of two types of achenes can be facilitated by the existence or lack of an inner pappus. This corresponds to the distinction between Achenes with an internal pappus and Achenes without one [20]. The findings indicate that the morphological characteristics of the achenes being studied have significant overall and particular advantages, as well as that their taxonomic significance is enhanced when analyzed alongside additional morphological attributes.…”

Morphological and Genomic Differences in the Italian Populations of Onopordum tauricum Willd.—A New Source of Vegetable Rennet

“…Significant differences between the two groups of populations were finally found in the size (height, width) and shape (BX, BY, perimeter, area) of the fruits. Indeed, micro- and macromorphological characteristics of Asteraceae achenes have been used for the identification and systematics of numerous genera [ 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 ] and have been found to be very useful for taxonomic diagnosis in many critical genera, such as Centaurea [ 74 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 ]. The characteristics that were found to be more diagnostic are: shape, size, pericarp texture and color, surface structure, hilum position, and pappus hairs.…”

Comparative Studies among some Cultivated species and their Wild relatives in Egypt using Phytochemical Screening, Nutritive value, Antioxidant Activity and GC-MS Analysis

“…There are about 25,000 species and 1600 genera in the Asteraceae family, which is also called the sunflower family. This family is very important because it contains a lot of biologically active substances, such as essential oils and polyphenolic compounds like lignans, saponins, polyphenolic compounds, phenolic acids, sterols, and polysaccharides (Rolnik and Beata, 2020;Shamso et al, 2021). They are also good sources of Na, K, Ca, and Mg, as well as vitamins A, B, C, and D.…”