I found this grouping of mushrooms in some fairly packed dirt near a busy sidewalk, on the grounds of a business park near downtown Sunnyvale. They seemed to emerge out of nowhere, intriguing me enough for me to document them photographically. I have now tentatively identified them as Pavement Mushrooms (Agaricus bitorquis), on the basis of the following key traits: 1) Spore print chocolate brown. 2) Mushroom with a veil when young that eventually collapses, forming an annulus (ring) around the mushroom's stalk. 3) Mushrooms with gills that are free (not attached to the stalk). [(1) - (3) are enough to place these mushrooms within the large family, Agaricaceae.] 4) Very base of mushroom's stalk not giving off an unpleasant odor resembling phenol or school paste when crushed. (Odor was slightly sweet and 'mushroomy') 5) Flesh of mushroom's cap not giving off a sweet odor, resembling almond extract or anise. (Odor was slightly acrid, not sweet-smelling at all.) 6) Flesh not staining red when cut or rubbed repeatedly. 7) Veil present, forming a large, band-like ring around the mushroom's stalk. (See Shot 5.) 8) Stalk solid, and texture of mushroom very firm when young. (See Shot 5.) 9) Found in hard-packed or disturbed soil. The lead shot of this set shows the mushrooms in profile, so that you can see the gills on the underside of their caps and some of the details of the stalk. The mature caps are larger and flatter than those of the younger mushrooms, reminding me a bit of the cultivated portabello mushrooms one finds in stores. These mushrooms are not nearly as large as the grocer's portabellos, as they range only between 2 and 3 inches in diameters. Shot 2 shows the mushrooms from a slightly different angle and a slightly closer distance. I shows how the surface of these mushrooms caps have cracked into scaled, a not uncommon occurrence for this species of mushroom. Shot 3 is an overhead shot, looking straight down at the surface of the mushroom's caps. It clearly shows the cracked, scaly patterns that have developed on the surfaces of their caps - apparently, not an unusual occurrence for this species. It also shows possible evidence of animals nibbling on these mushrooms; if you look carefully, you will see what appear to be bite marks that appear along the edges of their caps, unrelated to their cracked/scaly patterns. Shot 4 shows these mushrooms when I first discovered them, and they were still in the button stage of development and formation. Even at this stage, they were already beginning to crack and form a scaly pattern on the surface of their caps. Despite the cracking on their caps, these mushorroms still felt quite solid to the touch; there wasn't anything flimsy about them at all. Shot 5 shows the underside of the cap of one of these mushrooms, which someone had kicked over and upside-down on the ground. Shot 5 documents several key traits: (1) The gills being free from the stalk. If you look around the stalk, you will see that there is a space between the stalk and the proximal ends of the gills. (2) If you look part of the way down the stalk, you'll see the annulus or ring of material left behind by the collapsed veil. (3) Despite a number of slug- or insect-generated holes, this mushroom's stalk appears to be quite solid. Th first two field marks are important, in that they place these mushrooms in the family Agaricaceae. The third field mark is a clue as to its species. Because this individual mushroom had alrady been kicked over, I decided to take it home and study it further. This yielded some of the other field marks or key traits that I described in above. Photographed in Sunnyvale, CA, using a basic phone camera.