Excerpts from Jim Conrad's
Naturalist Newsletter

from the May 5, 2013 Newsletter issued from the Frio Canyon Nature Education Center in northern Uvalde County, southwestern Texas, on the southern border of the Edwards Plateau, USA
ROCKLETTUCE

Despite the drought, one wildflower fairly commonly appearing in open, rocky and grassy areas on our hills' lower slopes and even along roads is a modest little perennial with leaves mostly arising from the base, but with white, yellow-eyed, dandelion-like flower heads on slender stems rising about a foot above the ground. One is shown below:

Rocklettuce, PINAROPAPPUS ROSEUS

Below you can see how the stiff stems shoot from lobed leaves at the base:

Rocklettuce, PINAROPAPPUS ROSEUS, basal leaves

This is a member of that big group, or tribe, of Daisy or Composite Family members in which the flower heads bear only ray flowers with flat, shaped corollas -- no disc flowers with cylindrical corollas in the center. Besides dandelions, others in this group with only ray flowers include lettuce, chicory and our beloved sow thistles.

A close-up of a flower head showing that the white ray corollas are yellow at their bases is shown below:

Rocklettuce, PINAROPAPPUS ROSEUS, flower head

The flower heads' individual ray flowers don't look unusual but when you look beneath a head at the overlapping, scale-like bracts, or phyllaries, forming the greenish involucre, the phyllaries turn out to be fairly unusual -- good field marks, as shown below:

Rocklettuce, PINAROPAPPUS ROSEUS, phyllaries of involucre

They are broad and few with margins so thin or "scarious" that they're like cellophane. Even more distinctive is how the phyllaries end in sharp, dark brown tips turning purple lower down, before becoming greenish.

This plant produces fruiting heads very similar to Dandelion "puffballs," except that they're smaller and the fuzz is brownish or tan color. Below you can see a part of its fruiting head in which long, slender, cypsela-type fruits are topped with wind-catching fuzz parachutes:

Rocklettuce, PINAROPAPPUS ROSEUS, cypselae with brown hairs

This wildflower goes by the names of White Dandelion and Rocklettuce. It's PINAROPAPPUS ROSEUS, a genus I'd never heard of before coming here. It specializes in living in open limestone areas, roadsides, on cliffs and in open, grassy flats -- exactly as we see it here -- and is distributed from southern Arizona to Oklahoma, south through Texas and well into central Mexico's arid zones.

In Mexico, according to the online Biblioteca Digital de la Medicina Tradicional Mexicana, the Nahua people of Tlaxcala State -- who call the plant Chipuli -- traditionally daub the white latex that oozes from the plant's broken stem or leaves onto aching teeth. Also, mothers who want to break their babies from nursing smear the bitter latex on their nipples.