Micromorphological investigations on fruits of some taxa in the Tribe cardueae (Asteraceae)

The tribe Cardueae comprises more or less 500 taxa included 39 genera in our country, according to recent reports. In this study, fruit (cypsela) and pappus of 15 taxa, belonging to 10 genera in the tribe Cardueae were investigated, in detail by using stereo microscope and scanning electron microscope (SEM). Plant materials used in this research were collected from natural habitats during the vegetation periods of taxa between 2011 and 2017. The collected plants were dried and stores as herbarium specimens in Artvin Coruh University Herbarium (ARTH). Morphological studies were carried out from herbarium materials. Mature fruits and pappus obtained from herbarium samples or randomly collected in fields were used in SEM analyses. Cypsela shapes of the investigated taxa are obovoid, oblond, oblanceolat and obpyramidal, and while the smallest cypsela was found in C. sostitialis subsp. solstitialis, the biggest one was observed in Echinops orientalis among the investigated taxa. Carpopodium was detected in the fruits of Callicephalus nitens and Onopordum turcicum differently from other taxa. Based on cypselas surface ornamentation, scalariform, sulcate, tuberculate and rugulose fruits were detetmined. Pappus including caducous taxa, was obtained and their characteristics were given by using SEM analysis. It was observed that Picnomon acarna has the biggest pappus and C. calcitrapa subsp. calcitrapa has the smallest one. Pappus is determined as scabrous, subplumose and plumose, in addition, their bristles/hairs are present in above. On the other hand, it was detected that pappus diameter and frequency of bristles/hairs significantly differ among the investigated taxa.