Asteraceae, The Aster Family

At least 64 species of the Aster family grow naturally at Halibut Point, distributed among 27 genera.

Helianthus divaricatus, Woodland sunflower

It's not so hard to recognize the close relationship between asters and sunflowers. Their inflorescences are organized in the same composite fashion of single, brightly colored strap petals emanating from the ray flowers that surround the central button crowded with disc flowers bearing tiny, mute-colored petals.

Hieracium pilosella, Mouse-ear hawkweed

Lactuca  canadensis, Tall lettuce

The relationship between sunflowers and lettuce might not have been so intuitively grasped without a comparison of their respective flowers.

Lactuca biennis, Tall blue lettuce

The plumed seed heads of lettuce and of dandelions suggest that the family includes both of these members. The leaves of both plants are favored in salads.

Taraxacum officianale, Common dandelion

Cirsium vulgare, Bull thistle seeds

Thistle seeds likewise develop "sails" to help with dispersal into new colonies.

Bull thistle flower

The Bull thistle is composed entirely of disc flowers, all button and no surrounding corolla of splendid ray flowers. However it has developed other ways of attracting pollinators.

Arctium minus, Common burdock

The Burdock shows a similar reliance entirely on disc flowers. As in the case of the dandelion, pappus hairs at the base of the flowers develop into a dispersal unit. For the Burdock, hooked spines attach to passing animals to transport the seed head to distant territories.

Bidens frondosa, Devil's beggar-ticks

The hooked spines of Bidens carry seeds off individually rather than as a whole capitulum. However you will have noticed the effectiveness of the dispersal method if you brushed against the plant and picked up scores of seeds on your clothing.

Bidens frondosa flowers

Bidens rely primarily on disc flowers with a few ray flowers forming an incomplete outer circle.

Anaphalis margaritacea, Pearly everlasting

Anaphalis demonstrates another structural variation within the Asteraceae where profuse white sepals surround the yellow disc flowers rather than strap-petal bearing ray flowers.



Erechtites hieraciifolius, American burnweed

This arrangement also characterizes burnweed (above) and tansy (below).

Tanacetum vulgare, Tansy

Cichorium intybus, Chicory

Unusually, Chicory is a member of the Asteraceae bearing only ray flowers. I haven't yet discovered how that qualifies it as a composite. The clues and criteria of taxonomy form a very intricate scope of study that most of us accept as a field for experts, and we botanize innocently with their prescriptions until field guides change and we have to adapt to new names or charts.

Rudbeckia serotina, Black-eyed Susan

Meanwhile, a daisy is a daisy is a....