Excerpts from Jim Conrad's
from the March 23, 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
Though last spring we reported that the drought was holding back the usual show of wildflowers in the valley, this spring the drought is even worse and wildflowers are only a shade of what they were last spring. Still, some finally are emerging, and what a pleasure to find them. One of them is the modest little white-flowered one who here seems restricted to thin soil atop a few shaded, limestone boulders along the Dry Frio River floodplain, shown above.
The tininess of the flower can be judged by comparing it to my finger behind it. Also notice the blossom's yellow center, and the long, spreading hairs on the vegetative parts. A view of the flower's bottom side showing how the long hairs extend onto the green calyx below the corolla appears below:
A longitudinal section of the flower shows how the stamens with their dark, oblong anthers are attached by their filament bases to the corolla tube's yellow walls, below:
Experienced wildflower sniffers probably can guess that such a hairy, spring-blossoming little herb with small flowers with five stamens arising from the corolla tube's walls will be a member of the Borage or Bluebell Family, the Boraginaceae, and that's the case here. Moreover, if when you step from Juniper House and see the numerous tiny wildflowers conspicuously blossoming with bright, yellow flowers whose basic structure is the same as this flower's, and you know that those yellow-flowered plants are stoneseeds of the genus Lithospermum, you might further guess that this white-flowered, boulder-top wildflower also is a stoneseed, and you'd be absolutely right. The yellow-flowered one common around Juniper House can be reviewed at http://www.backyardnature.net/n/h/gromwell.htm.
Our white-flowered, boulder-perching stoneseed species is the Rough Stoneseed, LITHOSPERMUM MATAMORENSE. Stoneseeds in general also are called puccoons, gromwells and other names. Our Rough Stoneseed also is called Rough Gromwell and in Texas some call it the Rio Grande Puccoon. The "roughness" in two of the names is caused by the plant's mildly stiff hairs.
The yellow-flowered species is a widely distributed one but our boulder-percher is mainly a Mexican one found in central and northeastern Mexico, and extending into the US only in the southern half of Texas.
The boulder perching Rough Stoneseed isn't nearly as flashy as the yellow-flowered one, but its rarity and limited habitat make it worth looking for.