The Douglas Spring Trail begins in the Cactus Forest and ventures high into the Rincon Mountains of Saguaro National Park. It passes through 6 biotic communities between the desert floor (2,670') and highest peaks (8,666'): desert scrub, desert grassland, oak woodland, pine-oak woodland, pine forest and mixed conifer forest.

Saguaros are the largest of all cacti: they can reach 40' and weigh several tons

Saguaro National Park supports 25 species of cactus, most of which you'll find in the Cactus Forest

Jackrabbits are actually true hares, as they do not build nests; black tail jackrabbits inhabit all 4 southwestern deserts

The Rincon Mountain District supports at least 1200 plant species across 6 distinct biotic communities

Though its fruits are marginally edible, barrel cactus pulp is widely used for making cactus candy

Pleats in saguaro flesh expand like an accordion, allowing it to absorb as much water as its frame will support

Manzanita, distinguished by red smooth bark, means Little Apple in Spanish

Saguaros bloom April - early June; these creamy white flowers only open at night and close the following afternoon

The Doulgas Spring Campground is located in the Oak Woodland biotic zone

There are 6 rattlesnake species in Saguaro National Park, all of which inhabit the Rincon Mountain District

Saguaro cacti first form branches after 50 - 70 years; these saguaros may be over 200 years old

Teddy Bear Cholla have imperceptible barbs that can detach with the slightest touch, hence the nickname Jumping Cholla

The Douglas Spring Trail rises above the cactus forest into open Desert Grasslands and chaparral

Sotol is adapted to coarse textured soils in mid-high elevations

Barbed spines called glochids detach easily from prickly pear cactus pads, and are very difficult to remove

There are 3 types of yucca found in the Desert Grasslands and Oak Woodlands of Saguaro National Park

Saguaros range from sea level - 4,000' in the Sonoran Desert; any found higher are usually on south facing slopes

The Mexican Long-tongued and Lesser Long-nosed bats are two species that pollinate saguaros

The spines of most cholla are covered with a papery sheath that reflects sunlight and protects the stem from overheating

The landscape grows rugged and diversifies in the foothills over the Cactus Forest