Mile 0.0: Begin near the demonstration garden. Head west on Summit Loop Trail. The path splits after about 350 feet. Bear right, then cross the street. The first part of the trail runs parallel to Guadalupe Canyon Parkway, but Summit Loop Trail soon veers uphill into a quieter region. In spring, there is an amazing variety of wildflowers in a coastal scrub plant community. You might see wallflower, johnny-jump-ups, hummingbird sage, owl's clover, California poppy, and bluedicks. The ascent is on the easy side of moderate. Mile 2.0: Summit Loop Trail crosses a paved service road, then makes a final push for the ridge. In spring there are hundreds of irises hunkered down on the wind-swept hillsides. Mile 2.3: Summit Loop Trail crosses the road one more time, at the high point of the hike. I once saw a coyote along the road near here. The trail begins an easy descent, through ceanothus and coastal scrub. Mile 2.4: Junction with Ridge Trail. Continue straight on Summit Loop Trail. Mile 2.5: Bench with San Francisco city views. In April, when invasive spurge shrubs bloom, the hillsides on the north side of Guadalupe Canyon Parkway are tinted yellow. Mile 2.6: Junction. Turn right on Dairy Ravine Trail. Typically there are lots of spring wildflowers along the trail, including goldenfields, scorpionweed, buttercup, paintbrush, and checker-bloom. Mile 3.0: Junction. Dairy Ravine Trail ends here. Continue downhill, to the right, on Eucalyptus Loop Trail. As the trail winds down the mountain, there are views south, to San Bruno's lonely eastern slopes. It's an odd contrast to the visible and audible hubbub of South San Francisco and Brisbane. Mile 3.5: Eucalyptus Loop Trail ends back at the trailhead.
