Cow horn, Euphorbia grandicornis. Close view of tiny yellow flowers growing along edges of spiny, fleshy leaves.

Lily. Close cropped view of single flower of Arum lily with white spathe and yellow spadix.

Coneflower, Black-eyed Susan, Rudbeckia flowers with bright yellow petals surrounding central cone against blue sky.

Vitis vinifera Queen of Esther, close cropped view of red and yellow, variegated leaf.

Single, saucer-shaped flower of Cosmos bipinnatus Sensation Picotee with pink petals irregularly streaked with white and hoverfly on yellow centre.

Single, saucer-shaped flower of Cosmos bipinnatus Sensation Picotee with pinkish white petals irregularly edged in crimson surrounding yellow centre with hoverfly.

Single, saucer-shaped flower of Cosmos bipinnatus Sensation Picotee with pinkish white petals irregularly edged in crimson surrounding yellow centre.

Single, saucer-shaped flower of Cosmos bipinnatus with pale pink petals surrounding yellow centre.

Yellow flowers of Clematis tangutica.

Yellow flowers of Clematis tangutica with fluffy seedheads in foreground against blue sky.

Poppy, Papaver rhoeas Shirley series. Hoverfly on yellow stamen of single, open flower with shadow of seedhead on petal.

Pansy, Viola x wittrockiana. Single flower with ruffled purple-brown, veined petals extending dark to light from yellow centre.