notes ...Note: Larger versions of this image can be viewed at this Flickr link, and comments can be made here.
Found near the locale given as 'Yerba Buena' on the map on pg. 45 of the PDF here.
This plant was enchanting!! The long, slender corollas with their uniformly dense, speading, short pubescence (= ''hirtellous'') were delightful.
This species is very different from the Hedeoma nana I had seen in the east Mojave years earlier. Initially, its somewhat matted habit; small, round, glossy-green leaves; and long tubular flowers, all reminded me of another delightful plant I've rarely seen, Monardella macrantha. That species was also flowering nearby on our visit to the locale here on the crest (and I'd seen it 8 days earlier along the crest of the Santa Lucia Mountains of Big Sur :-). Both are members of the mint family, Lamiaceae...and while M. macrantha is hummingbird pollinated, my guess is that this plant is moth (and maybe also hummingbird) pollinated.
There are two Hedeoma species on the most up-to-date plant list for the Sierra San Pedro Martir given to workshop participants by Jon Rebman. They are H. martirensis and H. matomianum. And according to the 1999 paper here by Reid Moran, those two species and at least one more, H. tenuiflorum, are endemic to Baja California...with H. matomianum occurring near the southern end of the SSPM, and H. tenuiflorum occuring further south in the Sierra San Borja (and presumably throughout the Sierra La Libertad, from this web page). Only one species, H. martirensis, appears on the 2010 annotated plant list by Thorne, Moran & Minnich. That's presumably because the latter plant list only covers the high SSPM, and Cerro Matomi (the presumed locality for H. matomianum) is somewhat separated from the high SSPM to the south. And Wiggins in this case is woefully inadequate! It has only one species, Hedeoma nama ssp. californica...which is apparently an error! (I hadn't realized it, but Jon Rebman mentioned that there are literally hundreds of species that were not known or covered by Wiggins in 1980...so although it's a great resource, it's far from complete.)
So from all the above (together with the fact that Jon told us what the species was :-), we can conclude this is H. martirensis. Still, I like to key species new to me, to learn about their salient characters and other details, so I was happy to find a fairly recent (1980) treatment of the genus Hedeoma by R. S. Irving, with a key here. But, unfortunately, the key in that paper doesn't work very well for H. martirensis (and was made before H. matomianum was known). The species description can be read here...I was surprised it didn't mention that the long corollas are (exteriorly) hirtellous, which was one of the most striking and conspicuous characters of the plant in the field. (Perhaps its less so in aged, pressed, herbarium specimens.)
For a more detailed treatment and discussion of H. martirensis, the best place to turn is probably the original 1969 description by Moran, which can be read here. JSTOR has an isotype image, SEINET has two herbarium sheet images, and more field images of can be found on the SDMNH photo page (search under the species name there).
Finally, note that...once again...we have a species here that is endemic to the Sierra San Pedro Martir.