This is a shrub many allergy-sufferers come to know all-to-well: rubber rabbitbrush (Ericameria nauseosa previously Chrysothamnus nauseosus). It flowers in the late summer and early fall and is found throughout western North America.
There are lots of cool facts about rubber rabbitbrush, some of which you can find here.
One of the common names for this plant is saltlover (Halogeton glomeratus); its genus name Halogeton is Greek for salt neighbor, and is often used as the common name. It's nonnative, found in salty soils, and is considered in many areas to be a noxious weed. It grows throughout much of the western U.S. It concentrates sodium oxalate and is poisonous to livestock.
The stems are often red, and the flowers are small and inconspicuous.
You might not recognize this plant by its USDA Plants Database name: burningbush (Bassia scoparia formerly Kochia scoparia), but you might know it by its other common names, kochia, ragweed, summer cypress, fireball, and Mexican fireweed. It's native to Eurasia but is now widespread. Although many consider it a weed, it does have some forage, food, ornamental, and erosion control properties.
For more info on burningbush, click here.
This plant blends in well with the gravel, so I had to get down low to get a photo of it so you could get an idea what it looks like. It's flatcrown buckwheat (Eriogonum deflexum), part of the Buckwheat family (Polygonaceae). It grows in the desert southwest.
Flowers are rather inconspicuous.
This is a view of the plant from above.
A sprinkling of color along the roadside caught my attention as I was walking, and I found what looked like (and is) a native plant, still blooming in mid-September. A closer look at the flowers determined that this is in the Sunflower Family (Asteraceae), and a bit of searching narrowed it down to annual Psathyrotes (Psathyrotes annua). Other common names are mealy rosettes, fanleaf, and annual turtleback. It grows in shadscale communities and is found only in a few western states.
For more info on annual psathyrotes, click here.
This clover stands apart from other low-growing white ones by having a wooly head, hence the name woolyhead clove (Trifolium eriocephalum). It grows at lower elevations, often in wet meadows or pastures. It is found in the western U.S.
For more info on woolyhead clover, click here.
This paintbrush differs from others in the area in that it likes growing in wetlands or riparian areas, is an annual, and has a single stem. It's lesser Indian paintbrush (Castilleja minor formerly C. exilis). It grows in the western U.S. and Canada.
For more info on lesser Indian paintbrush, click here.
This bright blue flower growing along a streambank caught my attention. The six petals were a hint that it's in the Iris Family (Iridaceae). This is stiff blue-eyed grass (Sisyrinchium demissum), and it grows in many of the desert southwest states. The plant looks very much like a grass until it flowers, hence the common name.
For more info about stiff blue-eyed grass, click here.
This low-growing shrub, common at higher elevations, is common juniper (Juniperus communis), part of the Cypress Family (Cupressaceae). One interesting characteristic is that it has the greatest range of any woody plant in the northern hemisphere temperate area.
The juniper berries have a wide variety of uses, from Native Americans using them to treat diabetes to a flavoring for gin. For much more info about common juniper, click here.
I knew when I saw this plant it was in the genus Pyrola in the wintergreen family (Pyrolaceae), but my key is based on flowers and this wintergreen is in the fruiting stage. Fortunately, the wonders of the Internet made it possible to narrow it down to greenflowered wintergreen (Pyrola chlorantha). Leaves are simple and entire with white veins.
It grows through much of North America except the southeast.
For more info about greenflowered wintergreen, click here.
You probably know this flower--the common sunflower (Helianthus annuus). It's native to the Americas and widespread. Flowers can be highly variable in this annual plant.
Young sunflowers display heliotropism--that is, they turn their heads to follow the sun throughout the day.
I was delighted to see so many insects on the sunflowers, in particular this butterfly, a clouded sulphur (as best I can tell). With the yellowish tint, it's probably a male.
And the greener-tinged one is the female clouded sulphur. I saw thousands of sulphurs over an alfalfa field earlier in the summer, so it's neat to see what else they are feeding on.
I haven't seen many new plants blooming lately, so when I saw this one today, I was quite excited. It's thorn skeletonweed (Pleiacanthis spinosus, previously Stephanomeria spinosa), also called spiny skeletonweed. The plant is a wiry clump of thin stems and thorns, so the pinkish flowers are a bit of a surprise. It grows in much of the western U.S. and likes semi-arid habitats.
It's in the Sunflower Family (Asteraceae), one of the few pink flowers in the family.
This trumpet-shaped flower is Douglas's catchfly (Silene douglasii var. douglasii), part of the Pink family (Caryophyllaceae). It grows in western North America at mid to upper elevations. The name catchfly refers to the sticky stems and calyxes to which small insects may get stuck.
Not too far away I found this all white specimen, which I believe is still the same species, just with some color variation.
For more info about Douglas's catchfly, click here.
This is my least favorite weed: puncture vine (Tribulus terrestris), also known as goathead or caltrop.
The cute ferny leaves and pretty yellow flowers are deceiving, making it seem like a friendly plant. Puncture vine is in the Zygophyllaceae family, also known as the creosote bush family. My husband's favorite plant is creosote bush, so how is it possible that my least favorite plant is in the same family? 
Puncture vine is originally from the Mediterranean, but it has spread quickly. These trailing tendrils make it obvious why someone decided to call it a vine. What about the puncture part? Take a look at this next photo.
These little green fruits are fairly innocuous early in the summer, but the heat and dryness of hot days makes them get harder and harder...
...until they turn into sharp brown thorns that break apart and make even more sharp brown thorns. These thorns are so sharp that I've gotten a flat bicycle tire, a flat stroller tire, and a flat wheelbarrow tire. Needless to say, all of these tires now contain Slime.
While I was photographing the puncture vine, Desert Boy took a fall, landing right on top of a mass of it. He started crying immediately and I think he's joined me in calling this his least favorite weed.
Here are a couple of the thorns stuck in his hand. The seeds remain viable for three to seven years, so even though I have pulled every plant that I've seen in the yard, I'll probably have to keep after them for years. And unfortunately there are plenty of seeds just outside our yard.
This sub-alpine and alpine plant is elegant cinquefoil (Potentilla concinna), also called alpine cinquefoil. It grows in western and northern North America and is part of the Rose family (Rosaceae).
Leaves are very hairy with gray underneath.
This pretty alpine flower is moss campion (Silene acaulis). It flowers in July, growing in western and northern North America. It's a member of the Pink family (Caryophyllaceae), and grows in mounds, with last years growth diminished to grey areas.
For more info about moss campion, click here.
This is a thorny currant that grows at middle and upper elevations called gooseberry currant (Ribes montigeneum). It grows in western North America, and a pretty pink flower blooms in spring and early summer. Later a red berry appears that is sought after by wildlife.
For more info about gooseberry currant, click here.
This cute little yellow-flowered plant is Ross' avens (Geum rossii var. turbinatum), part of the Rose Family (Rosaceae). It looks somewhat similar to cinquefoil, but the leaves are more divided. Another distinguishing characteristic are the relatively long styles. It grows in sub-alpine and alpine areas throughout the western U.S.
Occasionally the plants grow singly, but often they grow in big groups.
For more info on Ross' avens, click here.
