A set of around 10 shallow digs 3-5 cm deep tipped me off. Raking back the layer of Redwood needles another 2-5 cm (total depth probably something like 4-8 cm) turned up a single fruitbody situated amongst a lot of branched white rhizomorphs (see photos). Soil and humus had a strong vegetal odor – not great but not particularly unpleasant.
Peridium blushed rosy and royal purple!
Cross-sectioned fruitbody shows many olive-colored locules (likely paler because the fruitbody is small and immature).

Apparently has not been recorded in Santa Cruz County since the 80s, and only found a few times anywhere in recent decades.

I counted about thirty fruitbodies of this species at this spot today, many thanks to Carol Selter for the tip on where to find them!

Spores inamyloid, smooth, tapered-ellipsoid to pip-shaped. Basidia clamped at base. Some basidia 2-spored. Pileipellis a cutis of inflated, minutely incrusted hyphae with small clamps; occasionally with small, diverticulae or "anastomosing with "H" connections"/fusions between hyphae.

Spores:
L x W= 9 x 5 µm Q= 1.8
L x W=8 x 6 µm Q= 1.3
L x W=9.5 x 6 µm Q= 1.6
L x W= 9 x 5.5 µm Q= 1.6
L x W= 8 x 5.5 µm Q= 1.5
L x W= 11 x 7 µm Q= 1.6

Average:
L x W: 9.1 x 5.8 Q = 1.6

I showed the California Young Birders group a series of Calochortus invenustus and kennedyi yesterday and we then found this beauty on the trail ahead. A hybrid between Calochortus invenustus and kennedyi.

The colouration is perfectly intermediate and there is only a faint trace of a green stripe on the underside (strong in most invenustus, absent in kennedyi).