This is a very distinctive and unmistakeable plant, growing 3-4 feet tall in only one place (that I know of) along the stream, and is fairly local in a few other locations. Yellow ray flowers and a cone shaped disk. The leaves are unmistakeable.
Corollas bilabiate? No. Flowers all perfect with strap shaped corollas? No. Rays present? Yes. Pappus of capillary bristles? No. Achenes with a pappus? Yes. Key HEach achene has a neighboring rather stout scale that is towards the outside of the inflorescence. Next to subkey H on page 839. Peeking ahead, I do see Rudbeckia!
Receptacle paleaceous? Yes, based on the huge scales next to each achene. Rays white or yellow? Yellow (10). Rays fertile? No -- mine have no pistil or evidence of one. (11) Rays sessile and persistent (i.e. is this Zinnia?)? No. (13) Involucre distinctly double? Not at all. (17) Achenes dorsoventrally compressed? No. (18) Plant scapose or otherwise? Otherwise. (19) Pales on the receptacle in a single series? No, all the achenes have pales (20) Leaves parted or entire? Parted - this is "cut leaf" coneflower after all. (21) Pappus a short chaffy crown or 1 or 2 awns? No awns --- Rudbeckia (56)One word here "dorsoventrally" is tricky. It means compressed as if by a force acting on the radius of the flower. Also the last question is clear only because my achenes have no awns, there is a tiny crown like part of the achene surrounding the flower and that must be what they mean.
The most interesting part about this inflorescence is the stout scale with a green spiky top protecting each achene.
Tall perennials. Leaves alternate, lower ones pinnately divided into few lobes. Upper leaves 3-cleft to entire. Heads large, radiate, yellow, involucre herbaceous or subfoliaceous, disk becoming cylindric, achenes 4 angled (yes). Pappus a short crown.
Rich soil along mountain streams to 8500 feet. July to September. A showy but rather coarse plant. (So they say).
Tom's Plant pages / tom@mmto.org