Saturday, May 26, 2012

Mt. Hough 3: Composites

The composites, which used to be in the Family Compositae, are now in the Family Asteraceae.  The earlier name was descriptive of the type of flowers, each "head" that looks like one flower is actually a cluster of "disc" flowers (the central portion of a daisy or sunflower) surrounded by "ray" flowers, each so-called petal actually being an individual flower.  The newer names follows a a rule that says a family name should be derived by its most typical genus, thus Asteraceae is named for the genus Aster of which we have several native species locally.  The most familiar members of this family have showy disc and ray flowers like daisies, sunflowers, fleabanes, and asters.  However, some members of the family have only disc flowers and others have only ray flowers.  I'll leave it to my readers to speculate on why they would thus qualify as members of a "composite" family.  It reminds me of the question my students ask, Why is the Legless Lizard still considered a lizard rather than a snake?  Fun stuff for the curious.
I have examples of several tricky composites in the above collection, especially ones whose flowers are so small that a hand lens is needed in order to recognize that they are composites.  If you've followed this blog for a while, you'll be amazed that I didn't include dandelions in this post.  I usually take every opportunity to shout in support of dandelions, so it took some real restraint not to do so this time.  From the top, plants with composite flowers I've found on Mt. Hough since Thursday:
Arrow-leaved Balsamroot, Balsamorhiza sagittata; Single-stemmed Groundsel, Senecia integerrimus; Pineapple Weed, Matricaria discoidea; Yarrow, Achillea millefolium; Mugwort (not yet blooming), Artemisia vulgaris; Sagebrush (not yet blooming, and close relative of Mugwort), Artemisia tridentata; Trail Plant (not yet blooming), Adenocaulon bicolor; Salsify, Tragopogon dubius; California Thistle, Cirsium occidentale. The Trail Plant, Mugwort, and Sagebrush have such tiny flowers that they usually go unnoticed. The flowers of the California Thistle will be bright red.
Other composites that are now blooming or will bloom soon include Mule's Ears, several species of Arnica, and several Asters.  Oh, one of my favorites: Gum Plant.  Some of these are beautiful in their own right, but some are especially interesting because they attract a wide variety of interesting pollinators and other guests.  I'll finish this series of Mt. Hough flora with a post on animals, including some of these insect and arachnid visitors.

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