This'll blue

 

Ready to blow away

 

A common thistle ( Cirsium vulgare ) seed pod has exploded, ready to send its seed on the next wind.

 

 

Stray seed

Thriving in a crack

A wayward seed found its way into a crack in the sidewalk.  Unmolested by passers-by, it grew to flower.  Note:  that may be a red spiked amaranthus.

This sidewalk survivor was seen, as a youngster, in Grow in a crack :

By a fence

Grow in a crack

The street beneath our feet is riddled with cracks and crevices.  These sidewalk shelters can provide a safe haven for wayward seeds.    

In a sidewalk expansion joint 

The shape of the air conditioner drip mirrors the spread of the plant.

By a fence 

The steps are color coordinated with the plant leaves.

Curbside 

Left undisturbed, their growth can enliven the cityscape.

Willow bloom for me

Spring means flowering willows.

Catkins with cottony seeds

This willow is an early bloomer and the cottony fluff is ready to be carried off by a breeze.

Black willow (Salix nigra) 

The black willow catkin looks like a multilegged caterpillar.

Pussy willow (Salix discolor)

These open pussy willow flowers show off their anthers with the yellow pollen.

Seed pod

This seed pod from the previous year awaits dispersal.

Maple copters

Maple seed pods

Maple (Acer spp.) seeds, also know as "helicopters", litter the sidewalk beneath our feet.