Butterfly Weed (Asclepias tuberosa)

Asclepiadaceae or Milkweed Family
(many botanists now lump this family in the Apocynaceae or Dogbane Family)
 

Tall plant with long, narrow, stalkless leaves crowned with brilliant orange flowers.  Each flower has 5 petals that curve back and and a crown formed of 5 fused stamens, each with a hood.

Occasional in dry to moist open areas, especially along the bikeway.

Unmistakable.  There are few plants with orange flowers to begin with. Only milkweeds have flowers with such an odd structure, but no other milkweed has orange flowers.