Excerpts from Jim Conrad's
Naturalist Newsletter

Lawnflower, CALYPTOCARPUS VIALIS, leaves and flowering heads

from the November 18, 2012 Newsletter issued from the valley of the Dry Frio River in northern Uvalde County, southwestern Texas, on the southern border of the Edwards Plateau, USA
LAWNFLOWER

Nowadays in the weedy grassy area around the cabin there's a small, sprawling herb with tiny yellow blossoms only about 5/16ths inch across (8mm). It's a member of the Composite or Daisy Family, so what look like petals are actually ray flowers. Normally ray flowers are fairly evenly distributed around a composite blossom's perimeter, but these flower heads are so small and the ray flowers so few that often they look randomly placed, giving the little blossom a haphazard appearance. All this is shown above.

Once the flowers are pollinated, as is normal for composite flowers, the corollas fall off, the remaining seed-like, dry, one-seeded fruit (a cypsela) expands, and the scaly pappus atop the cypsela also expands to form become a crown of spiny "awns" atop the cypselae, which typically aid in fruit dispersal. These upward projecting spines atop some cypselae are shown below:

Lawnflower, CALYPTOCARPUS VIALIS, awns atop cypselae

You probably noticed that this is a hairy little plant. Just for the fun of it I photographed some hairs on the bottom of a leaf, as shown below:

Lawnflower, CALYPTOCARPUS VIALIS, hairs on bottom of leaf

Around here this is a very common, weedy herb in lawns and along roads and trails. It's a native American species, found from South American north through Central America and Mexico into the US Deep South. This native American species, however, has "gone weedy" in many warm, moist countries. Despite being so common and widespread it has no English name most people have settled on. My Field Guide to Southwestern and Texas Wildflowers calls it Lawnflower, but elsewhere it's called Straggler Daisy, Sprawling Horseweed, Horseherb and other names. It's CALYPTOCARPUS VIALIS.

This little herb attracts small butterflies like sulfurs and skippers. Altogether it's a fine little plant, its yellow blossoms very pretty in the dark-green grass that at this time of year with sunlight's intense light and shadows, esthetically, seems "just right."