Thursday, September 24, 2015

The Daisy Family, Part 1

Leopard's bane, Doronicum pardalianches
Daisy, from 'Day's Eye' in Old English, a flower opening with the dawn and closing at dusk, is forever linked to sunny faces and carefree spirits.

Chicory, Cichorium intybus
The unifying trait of the daisy family is its composite flower construction. Compositae family members come in many colors and configurations.

Pearly everlasting, Anaphalis margaritacea composed of disc and ray flowers
Composites give the impression of being a single flower. The inflorescence actually consists of a central cluster of many petal-less disc flowers (yellow in the photo above) encircled by strap-like ray flowers.
Fall dandelion, Scorzoneroides autumnalis consists of ray flowers only
The  ray flowers generally have five petals each, greatly modified to attract pollinators. The minute notches at the end of each dandelion ray trace the originally separated petals of each flower in the composite.

Exceptionally, dandelions have no disc flowers.
Rayless chamomile, Matricaria discoidea with disc florets only
On the other hand, the button-shaped rayless chamomile consists entirely of disc flowers whose corollas are fused into tiny tubes.  Their pollination is primarily accomplished by flies.

Tansy, Tanacetum vulgare
The tansy is likewise composed exclusively of disc flowers. It  colors them brightly enough to attract a wide range of pollinators.

Ragweed, Ambrosia artemisifolia
Composites with wind-pollination strategies have forsaken eye-catching flowers altogether. Plants in the ragweed and artemesia group release copious pollen into the air, a major source of allergens to humans.
Blunt-leaved rabbit-tobacco, Pseudognaphalium obtusifolium
Evolving from a common origin, or at least a common principle, the Compositae have diversified along ingenious pathways of species development. A family gathering of composites presents whimsical personalities.
Three-leaved rattlesnake-root, Nabalus trifoliolatus
Nabalus trifoliolatus flower detail
Mouse-ear hawkweed, Hieracium pilosella

Spotted Joe-Pye weed, Eutrochium maculatum
Yellow thistle, Cirsium horridulum
Bull thistle, Cirsium vulgare
Tall lettuce, Lactuca canadensis
Familiar though we are with lettuce foliage few of us would associate it with the daisy family. By the time these head-high flowers bloom at Halibut Point there is little about the basal leaves to remind us of a culinary staple.
Woodland sunflower, Helianthus divaricatus
But sunflowers proclaim their composite nature unmistakably.

Ox-eye daisy, Leucanthemum vulgare 
And of course the ox-eye daisy carries the daisy message over hill and dale as the emblem of summer gaiety.

 In searching out the scope of the daisy family at Halibut Point I have encountered about seventy species in thirty-six different genera. They are more or less conspicuous, and more or less distinguishable from one another.
In September the most complex branches of the Compositae, asters and goldenrods, brighten every corner of the landscape. I look forward to bringing them center-stage in next week's essay.

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