Excerpts from Jim Conrad's
from the July 13, 2014 Newsletter issued from the Frio Canyon Nature Education
Center in the valley of the Dry Frio River in northern Uvalde County, southwestern Texas, on the southern border of the Edwards Plateau, USA
Fogfruit "weeds" are abundant along roads and other disturbed areas in the upper Dry Frio River Valley. You can see the species common there at http://www.backyardnature.net/n/h/fogfruit.htm.
On low, frequently walked-upon levees between ponds in Cooks Slough Nature Park on the south side of Uvalde, fogfruits also are abundant, forming dense, green carpets that nowadays are pretty with whitish flowering heads. However, these levee fogfruits somehow struck me as different from those in the Dry Frio Valley. Above you can see the levee ones to compare with those of the Dry Frio Valley.
I can't see much difference between flowers of the two species. Flowers of this week's levee species are shown below:
One interesting feature of fogfruit flowers is that when the blossoms are ready to be pollinated their centers are yellow but once the flowers are pollinated the centers turn reddish. That's because the spectrum of colors visible to insects is a little higher in frequency than what humans see. The lowest frequency of color we see, red, is invisible to insects. Therefore, when fogfruit's flower center turns red, it becomes darker and less attractive to insects, who then pay more attention to the yellow-centered flowers needing their pollination services.
Though the flowers aren't much different between the two species, the leaves are. The levee species' leaves are shown below:
The levee species' leaves are broadest at their outer ends, instead of at or below their middles. Also, the levee species' leaves have margin teeth restricted to their outer end, while leaves of fogfruit in the Upper Dry Frio Valley have teeth below their middles.
Our levee species is PHYLA NODIFLORA, in the US commonly occurring from coast to coast in the southern half of the country, plus it often grows weedily in nearly all the rest of the warmer countries of the world.
We have two common fogfruit species in our area, and two more might possibly turn up. Phyla nodiflora is separated from all of them by having this combination of features: The shape of its leaves is broadest and toothed only at the blade's outer half, and; the flower heads are held on stems, or peduncles, two or more times longer than the leaves below them.
This name "fogfruit" is a bit clumsy to use. For one thing, the terms fogfruit and frogfruit are almost equally recognized, and both names are a little silly since the plants' fruits have nothing to do with either fog or frogs. The name "fogfruit" is said to have appeared in print some years before "frogfruit" so I use that here. Phyla nodiflora also is known as Turkey Tangle Frogfruit, Sawtooth Fogfruit, Frogsbit, Licorice Verbena, Capeweed, Creeping Lip Plant, and many other names. But this is one case in which technical binomial names don't instantly save us, for even specialists can't agree on one name, some calling it Phyla nodiflora while others use Lippia nodiflora.
Happily, this pretty little plant doesn't need a name humans are content with to do its ecological service of providing nectar to pollinators, forage for certain grazers, and creating a pretty carpet that keeps down soil erosion in places where the soil has been disturbed.