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Asclepias fascicularis

Common name: Narrowleaf Milkweed, Mexican Whorled Milkweed

Asclepias fascicularis is one of the primary food sources for the monarch butterflies. Ideally, it would be a part of every native plant garden in California, and beyond.

Typical for the milkweeds, the flowers are astonishingly complex. The Wikipedia page for Asclepias describes them in general and in A. fascicularis, I particularly like the little white “claws” or horns that come out of the each of the five hoods. The flowers smell floral, almost rose-like.

When the follicles (seed capsules) dry, they eventually burst open and reveal irregularly shaped brown seeds with white hairs — these silky white hairs are what gives the milkweeds in general their German common name “Seidenpflanze” (silk plant).


Here are my photos of Asclepias fascicularis. I first saw it at nearby Lake Hodges, sometime in September 2017, but it was already past its bloom by then. In 2018 it had completely slipped my attention but in 2019, I was able to make a nice series of photos. In September 2020 I was able to add the photos of the seeds to my collection.


Looking for the origin of the genus name Asclepias, one can find slightly contradicting, but nevertheless complementary information: Carl von Linné described milkweeds first in 1753, and supposedly derived the name Asclepias from the Greek god of medicine and healing, Asclepius — apparently because the plants have a long history of being used in traditional medicine. On the other hand, according to Wiktionary, Asclepias comes from the Latin adaptation of the Greek word for “swallow-wort” — but this also hints at the medicinal use.

The epithet fascicularis can be easily explained with the English fascicle, meaning a bunch or small bundle — this perennial plant grows many thin stems out of a single, woody rhizome.

Last not least, the “whorled” in its common name “Whorled Mexican Milkweed” refers to the long, thin leaves which tend to twist into whorls as the plant matures.


More about Asclepias fascicularis on CalFlora, Jepson eFlora, Wikipedia.

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