Asclepias syriaca (Common Milkweed) Asclepiadaceae (Apocynaceae)

The common milkweed, Asclepias syriaca, presents a wonderful example of the concept of “hidden in plain view.”

In 1758, Carl Linnaeus received a specimen of this species from a garden in the Levant. Accordingly, he named it Asclepias syriaca, assuming that it was native to Syria. Most people today, even when they don’t know the derivation of the specific epithet syriaca, assume the species is introduced, because they usually see it along roadsides in the company of other weeds, most of which are exotic invasives.

Although it is common and pale in color, a closer look will reveal amazing beauty and appreciation for detail.

 

 

Physical characteristics

Leaf: The leaves are opposite, up to 8” long and 3½” wide, broadly oblong in shape, and smooth along their margins. There is a prominent central vein along the length of each leaf.

Flower | Seeds: The flowers of the common milkweed are rather small and grow in a somewhat sparse inflorescence (compared to the Orange Milkweed [Asclepius tuberosa] or the Purple Milkweed [Asclepius purpurea] where the inflorescence is tightly packed). Each flower has 5 showy hoods that extend slightly past a hook in the center of each. The petals are flexed backward toward the pedicels. 

Trunk | Bark: The stem is herbaceous and will exude a white milky latex if broken.

Fruit: The fruit is a pod (see sidebar) covered in little spikes. This is the only milkweed to have its pod covered like this. Inside the pod are fibers, seeds, and more milky latex.

 

Ecological characteristics

Species List 

• Student Projects

• Image Gallery