notes Stems and leaves of the shrub Malacothamnus aboriginum. Many such plants were growing a few hundred feet south of the trailhead to Laguna Mountain. Malacothamnus can be tricky & difficult to ID to species. Per the insights of Keir Morse, I supplemented use of the Jepson eFlora key (which has some rather ambiguous and/or difficult-to-interpret key breaks, e.g. at couplets 3 & 4) with the keys in Munz(1959) and Kearny(1951). I arrived at M. aboriginum in all three, and the descriptions seemed to fit well in each (see Jepson eFlora; Munz; Kearny). So did those of the synonyms Malvastrum aboriginum in Gray(1897) and Sphaeralcea aboriginum in Jepson(1936).
Add to all the above the fact that a CalFlora search for collection records for Malacothamnus species within a large polygon containing Laguna Mountain (and much of the Clear Creek Management Area) returned many records for M. aboriginum...and none for any other Malacothamnus species.
So this is perhaps the most clear-cut experience one can expect for keying a Malacothamnus to species! :-)
Some salient characters for this species are: inflorescences not solely in terminal heads...mostly in leaf axils along main stems, sessile or short peduncled (i.e. < 1 cm)...with flowers in tight, sessile clusters; bracts subtending calyces basally fused in threes and widely ovate-deltate (rather than linear); calyx lobes more or less cordate at base with apices acute to acuminate; flowers in bud somewhat 'shriveled' along sinuses between calyx lobes (5-pointed star-shaped in cross-section); herbage with dense, but relatively short and tight vestiture of (many-rayed) stellate hairs; leaves ovate, 3(-5) lobed with crenate margins, cordate bases, and fairly long petioles (especially proximally).
