The plant is almost certainly a perennial. The flower is 1 cm across with both ray and disc flowers. Ray and disc are both yellow. My flower has 13 rays, though it might orignally have had 16. Ray flowers have a pistil, no anthers. Stem, phyllaries, and base of leaves covered with stout glandular hairs. No strong smell to foliage.
My first hunch, based simply on this being a small shrub-like Asteraceae growing out of a rock was that this was a Perityle (rock daisy). Perityle in the Arizona Flora key has disc flowers only. The genus description mentions white ray flowers. The photo of Perityle coronopifolia in Frank's book clearly has white ray flowers. At any case, my plant has yellow ray flowers, so this won't do. Not only that, the pappus is supposed to be just 1 or 2 awns and a crown of squamellae.
Corollas bilabiate? No. All flowers strap shaped? No. Are rays present? Yes. Pappus of bristles? Yes.I have had to take tweezers and pull out both a ray and disc flower to answer the last question. (And in truth, to verify the answer to the first question). This takes me to F in the key on page 836
(1) Rays yellow (not white, etc.)? Yes. (8) Pappus of squamellae or palea dissected into bristles? No, just bristles. (10) Leaves alternate or opposite? Alternate. (14) Pappus of 2 to 8 caducous bristlelike awns, plant glutinous? No.I see at least 12 bristles as the pappus. Caducous means they fall off early, no sign of that. Glutinous means stick or gummy, and not that either.
(15) Pappus wholly of numerous simple and capillary bristles? Yes. (16) Phyllaries in one series, style tips truncate? No.The Phyllaries on my flower are not all equal, and the style tips seem nicely pointed.
(18) Heads small, very numerous (Solidago)? No.This leaves me at Aplopappus. Heads usually few and relatively large. Aplopappus is page 858 in Arizona Flora. Already we are in trouble. None of my other books have this genus, but perhaps this is now Haplopappus. If so, even this is little help as Haplopappus has now been distributed in various other genii, including Xanthisma and others. But let us continue with the Aplopappus key in Arizona Flora on page 858.
(1) Plants with strictly herbaceous stems? Yes. (2) Heads discoid or radiate? Radiate. (3) Leaves strongly 3 veined? No. (5) Leaves entire or serrate? Entire. (6) Heads 1 to 3 per stem (or many)? Just one.Aplopappus croceus - This is reported from Northern Arizona only, San Francisco Peaks, White mountais, Mogollon rim. My plant looks nothing like this (now Pyrrocoma crocea). This is clearly wrong.
Maybe we went wrong with the first Aplopappus question, let us take the other branch (plants shrubs or undershrubs).
(9) Heads solitary at tips of branches? YesA. linearifolius Doesn't seem likely. And the "linearifolius" does not describe my plant which has small ovate leaves.
There is no key to the 25 tribes. Common tribes are given unique color codes. Less common ones are simply given "grey" as a color. No luck yet.
Tom's Plant pages / tom@mmto.org