CA, Southern California, 20071002
Madison Heights, two mushrooms.

Agaricus bitorquis []

Three trees east of NE corner of Fillmore and Los Robles; in hard-packed dirt at foot of camphor tree.
GEN med-large mushroom, in dirt at base of camphor tree, several loosely grouped
ST 30x25mm, tapering strongly to tip, solid, firm, obvious sheath-like ring at top opening both above and below
CAP 70mm wide, convex to plane, smooth whitish almost shiny, lots of dirt on cap, barely raised above ground, marg curled under, K-
FLESH white, firm, 15-20mm thick(!), staining weakly rufescent, mild pleaseant fungal flavor
GILL pink to brown, free, etc.
SPORE print brown (scanty), ellip, brownish, smooth, one big bubble, 6.6-7.6x4.3-5.3um
Clearly in section Agaricus Bitorques due to K-rufescence and sheath-like ring.

Calvatia booniana []

Huge! Two houses east of the Agaricus above, in lawn. I'm guessing since I didn't want to offend the owner by vivisecting their gorgeous giant puffball. ;)
GEN solit, in lawn
ST root like thing underneath
CAP huge (20-30cm?), whitish, smooth with v thin faint brownish areoles, rind 2mm thick & white, not bruising, K-
FLESH spongy, whitish, turning brown, featureless
SPORE will never mature, clear, smooth to v weakly textured, ellip to round, knobbed, 4.3-4.9x3.4-3.9um
Can you believe it?! They threw it away! The nerve of some people. Fortunately I found it in the trash. The spore mass will never fully mature, but there's enough there to let me ID it, at least.

(20071014) Darvin has convinced me that Arora is unreliable here C. gigantea does not occur west of the Rockies. C. booniana it is, then.

Pisolithus arrhizus []

The dusty blackish mass in the dirt under the first oak is (was) it a puffball?
GEN puffball, in dirt
CAP ~20cm wide?, gnarly lobed brown-black thing, rooted underneath at center, skin looks to have been fairly smooth but it's quite old
FLESH shows clear 5mm-wide chambering, rich deep brown, powdery, brittle
SPORE 7.5-9.5um, round, brown, v short-spiny all over, extremely hydrophobic
Basing ID on chambered firm spore mass, smooth skin, and spiny round brown spores that are exactly like those of S. cepa I've seen before. Wait! No! It's the "mushroom of the month" on BAMS couldn't be more clear, now that I see it. I just ignored the "sticking out of the ground like a dusty root" couplet in Arora, silly me.

Agaricus xanthodermus []

Just took a few more photos, same place, same crop.

Panaeolus foenisecii []

Just wanted to get some good pictures of the spores.
SPORE 13.1-16.4x7.2-8.9um