Sticky snakeweed
Gutierrezia microcephala
Asteraceae
[Possibly named for Pedro Gutiérrez Bueno. 1745-1826]

Hoary aster
Dieteria canescens var. canescens
Asteraceae

Heermann's buckwheat
Eriogonum heermannii var. argense
Polygonaceae
[Named for Adolphus Lewis Heermann, 1821-1865]

Thurber's penstemon
Penstemon thurberi
Plantaginaceae
[Named for George Thurber, 1821-1890]

Desert milkweed
Asclepias erosa
Apocynaceae

I had no idea what those structures were in the picture on the right, and have never seen any pictures showing this feature, so I asked Jim Andre about it, and wasn't surprised when he knew exactly what they were. Here's what he said: "That is the dried fruiting capsule or follicle split open at the suture (not visible in photo), the exterior turns tan and is usually smooth but can also have bumps or tubercles, as shown in your image. Typically one has to be out and about in late summer to see them looking like this, and most botanists aren't out then. What's unusual about your image is that it appears as though the tapered end of the capsule was lopped off, giving the appearance of a broad cylindric and open-ended capsule. I haven't seen that as a regular occurrence so I have to wonder if wind or other mechanical force caused it, or it if's just they way they break apart." Thanks, Jim.

Little-leaved brickellbush
Brickellia microphylla var. microphylla
Asteraceae
[Named for John Brickell, 1749-1809]

Mojave prickly pear
Opuntia polyacantha var. erinacea
Cactaceae