Flora & Fauna – SR18

Highest Concentration of Botanical Biodiversity in Utah

The area that State Route 18 traverse's is massive! Below is an excerpt from Wikipedia talking about the diversity of Flora and Fauna in the Pine Valley Mountains alone. Not to mention Red Cliffs National Conservation Area, Snow Canyon State Park, Red Mountain Wilderness and Dixie National Forest to name a few. The drive up highway 18 from St. George gives you an "up-close" look at 170 million years of world-class geology. The highway traverses through the transition zones of the Mojave Desert, Colorado Plateau and Great Basin Range.

The Pine Valley Mountains support spruce-fir forests, including a large stand of virgin Engelmann spruce. The mountains also have numerous meadows up to 50 acres (20 ha) in size.^[9] Several threatened, endangered, and sensitive species live in the mountains, including Bonneville cutthroat trout, Townsend's big-eared bat, and the pygmy rabbit, among others.

Botanically speaking, Pine Valley Mountain is the most diverse mountain range in Utah. A floristic survey was conducted between 1985 and 1987 and 967 species were collected.^[11] Since then, additional species have been added bringing the total to nearly 1,000. Three species new to Utah were identified including bitter cherry (Prunus emarginata (Dougl.) Walpers), common sandweed (Athysanus pusillus (Hook.) Greene), and Lemmon's onion (Allium lemmonii S. Wats.). Nineteen ferns and fern allies are present, 18 gymnosperms (conifers and Mormon teas), 150 species of monocots (including 86 grasses, 10 orchids, and 2 agaves, among others), with the remainder being dicots. The three largest families represented in the flora of Pine Valley Mountain include the Asteraceae with 160 species, Poaceae with 85 species, and Fabaceae with 63. The three largest genera and number of species collected are Eriogonum, 23, Cryptantha, 20, and Astragalus, 20. Some of the finds include:

Forked spleenwort (Asplenium septentrionale (L.) Hoffm.), a small grass-like fern found at a single high-elevation location north of Mill Flat.
Grape fern (Botrychium) found in the high meadows.
Young bristlecone pines (Pinus longaeva D.K. Bailey) are found along the very crest of the mountain especially near the summit of the Oak Grove trail and westward.
Sequoia tree (Sequoiadendron giganteum (Lindl.) Buchholz). A single tree planted behind the Browse guard station is almost four feet in diameter.
Pistachios have escaped cultivation from old plantings near Leeds and Harrisburg. The rootstocks for those orchards were the Mount Atlas pistachio (Pistacia atlantica Desf.) while the upper portions of the trees were the edible pistachio (Pistacia vera L.). Some of the tops have died and trees have resprouted from the rootstocks and produced viable seeds. Birds have helped move them into the southern foothills of Pine Valley Mountain where they have become naturalized, often growing as bonsai trees out of cracks in rocks and cliffs.
Dollarjoint cactus (Opuntia chlorotica Engelm. & Bigel.) scattered along the southern foothills.
A yellow-flowered population of Bridges penstemon (Penstemon rostriflorus Kellogg), along the south fork of Pinto Creek.
Three species of orchids in the genus Corallorhiza.
Pine Valley goldenbush (Ericameria crispus (L.C. Anderson) G.L. Nesom), with its peculiar crinkled leaves, is only found in the Pine Valley Mountains, most commonly along the Whipple Trail in Hop Canyon.
Utah spikemoss (Selaginella utahensis Flowers) has an extremely limited distribution in southwestern Utah and one location in Nevada, but is locally common on Pine Valley Mountain wherever a shady spot and Navajo sandstone can be found together.