Onopordum
Videos
Onopordum, or cottonthistle, is a genus of plants in the tribe Cardueae within the family Asteraceae. They are native to southern Europe, northern Africa, the Canary Islands, the Caucasus, and southwe
Onopordum bracteatum 0
Cotton thistle (Onopordum acanthium) from Thomé Flora von Deutschland, Österreich und der Schweiz 1885
Onopordum leptolepis
Onopordum leptolepis in bloom
Achene
Videos
An achene, also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent.
Onopordum
…smooth to slightly pubescent. These plants propagate only by seed. The seed heads mature in mid-summer, releasing their seeds. The fruit is a glabrous achene, 4–6 mm long and with 4-50 ribs. The pappus consists of many rows of simple, fine to minutely rough hairs, united in a circular base. Onopordum species…
Cypsela of Cynara
Cypselae on a dandelion "clock" (the matured capitulum) can disperse in the wind due to the hair-like calyx tissue above each ovary.
A microscopic view of a dandelion "clock" showing the receptacle and the cypselas.
Samaras of Acer buergerianum are achenes with large wing-like structures.