Cardoon, Cynara cardunculus, Seedhead with snow on it viewed from beneath.

Cardoon,Cynara cardunculus, Several stems of seedheads with snow and frost on them, against a pale blue sky.

Cardoon,Cynara cardunculus, Several stems of seedheads with snow and frost on them, against a pale blue sky.

Cardoon,Cynara cardunculus, close view of snow capped seedhead.

Dandelion clock, Taraxacum officinale. Digitally manipulated image of three dandelion seedheads within circle against softened, muted background creating effect of illustration.

Thistle, Onopordum acanthium. Scotch or Cotton thistle single flower stem with spiny leaves, base of flower and bracts.

Sea holly, Eryngium zabelii Big Blue, Close view of thistle-like flower head surrounded by silvery blue bracts.

Sea holly, Eryngium zabelii Big Blue, Close view of thistle-like flower head surrounded by silvery blue bracts.

Sea holly, Eryngium x zabelii Jos Eijking. Thistle-like flower heads surrounded by spiny, silvery blue bracts.

Sea holly, Eryngium x zabelii Jos Eijking. Thistle-like flower heads surrounded by spiny, silvery blue bracts.

Sea holly, Eryngium x zabelii Jos Eijking. Thistle-like flower head surrounded by spiny, silvery blue bracts.

Spherical seed heads of Globe thistle, Echinops cultivar.