Taxonomic significance of morphological and elemental characteristics of achenes of Artemisia genus from Turkey

In the study, the achene macro and micro morphological characters of the genus Artemisia distributed in Turkey have been researched with the target to know systematically important carpological structures for the examined species. Color, shape and dimension of achene have macro-morphologically shown variations. The examined achenes are separated into 4 shapes; fusiform-oblong, oblong, oblong-ovate and ovate. Oblong-ovate is the most common type. However, oblong is typical form for A. abrotanum . Achene dimensions range from 0.62 mm to 2.48 mm in length, from 0.30 mm to 1.21 mm in width. As A. santonicum subsp. patens is of the largest achenes , A. annua and A. verloitorum have the smallest achenes. Also, carpopodium diameter vary between 0.10 mm and 0.19 mm. The largest carpopodium diameter is found in taxa A. fragrans and A. taurica var. vanensis , while the narrowest one is A. alpina species. Achene surfaces of the examined taxa are micro-morphologically assessed, and the substantial differences are noticeably detected on behalf of the surface structures for instance, surface ornamentation, anticlinal and periclinal cell walls, epidermal cells and presence of secondary structures of the achenes. Surface ornamentation is separated into 10 types: irregularly sulcate, regularly sulcate, ruminate, sulcate-scalariform, rugose, favulariate, slightly sulcate, alveolate, tuberculate and reticulate. The most common types are irregularly sulcate (in 7 taxa) and regularly sulcate (in 7 taxa), while ruminate (in A. abrotanum ), rugose (in A. chamaemelifolia ), favulariate (in A. arborescens ), alveolate (in A. santonicum subsp. patens ), tuberculate (in A. taurica var. vanensis ) and reticulate (in A. bashkalensis ) ornamentation types are found as taxon-specific. A percentage comparison of the elements in the achene pericarp of the studied taxa have performed with SEM-EDS. Accordingly, pericarps in taxa include C, Ca, K, Mg, Cl, Si, Na and S elements. The most common seen element is C, which ranges from 77.4 (in A. austriaca ) to 96.2 (in A. absinthium ). Na element is observed only in A. santonicum subspecies and A. arborescens species. On the other hand, S element is found in low amounts only in A. alpina species. In the taxonomy of the genus Artemisia , the achene morphological characters are very significant characteristics that disclose inter-specific relations among the examined taxa. Moreover, a dichotomous key is offered for the identification of the studied taxa based on achene characters.