Tim Fitzharris / Vervain (Verbena officinalis) at Franklin Mountains State Park, Chihuahuan Desert, Texas

Tim Fitzharris / Temple of the Sun with Sunflowers in the foreground, Capitol Reef National Park, Utah

Kevin Schafer / Hedgehog Cactus (Echinocereus sp) blooming, Zion National Park, Utah

Kevin Schafer / Kousa Dogwood (Cornus kousa) blooming in spring, Seattle, Washington

Tim Fitzharris / Phacelia (Phacelia sp) and Hillside Daisy (Monolopia lanceolata) flowers, superbloom, Temblor Range, Carrizo Plain National Monument, California

Tim Fitzharris / Hillside Daisy (Monolopia lanceolata) flowers, superbloom, Temblor Range, Carrizo Plain National Monument, California

Tim Fitzharris / Phacelia (Phacelia sp) and Hillside Daisy (Monolopia lanceolata) wildflower bloom, Temblor Range, Carrizo Plain National Monument, California

Tim Fitzharris / California Desert Dandelion (Malacothrix californica) flowers and Ocotillo (Fouquieria splendens) in spring, Joshua Tree National Park, California

Tim Fitzharris / California Poppy (Eschscholzia californica) flowers in spring bloom, Diamond Valley Lake, California

Tim Fitzharris / California Poppy (Eschscholzia californica) flowers in spring bloom, Diamond Valley Lake, California

Tim Fitzharris / California Poppy (Eschscholzia californica) flowers in spring bloom, Lake Elsinore, California

Tim Fitzharris / Rubber Rabbitbrush (Chrysothamnus nauseosus) blooming near Cottonwood (Populus sp) trees in sand dunes in winter, Mount Herard, Great Sand Dunes National Park, Colorado

Tim Fitzharris / Rubber Rabbitbrush (Chrysothamnus nauseosus) blooming near Cottonwood (Populus sp) trees in sand dunes in winter, Mount Herard, Great Sand Dunes National Park, Colorado

Steve Gettle / Dwarf Crested Iris (Iris cristata) and trillium on forest floor, Great Smoky Mountains National Park, Tennessee

Cyril Ruoso / Strawberry Cactus (Echinocereus enneacanthus) blooming, southern Texas

Cyril Ruoso / Ladyfinger Cactus (Echinocereus pentalophus) flower, southern Texas

Cyril Ruoso / Engelmann Prickly Pear (Opuntia engelmannii) cactus blooming at night, southern Texas

Cyril Ruoso / Yucca (Yucca torreyi) blooming at night, southern Texas

Cyril Ruoso / Horse Crippler (Echinocactus texensis) cactus blooming, southern Texas

Cyril Ruoso / Horse Crippler (Echinocactus texensis) cactus blooming, southern Texas

Tom Vezo / Evening Primrose (Oenothera sp) flowers in desert, Joshua Tree National Park, California

Tom Vezo / Evening Primrose (Oenothera sp) flowers in desert, Joshua Tree National Park, California

Kevin Schafer / Tickseed (Coreopsis calliopsidea) and Foxtail (Vulpia sp), Carrizo Plain National Monument, California

Tim Fitzharris / California Poppy (Eschscholzia californica) covered hillside, spring, Tehachapi Hills near Gorman, California

Tim Fitzharris / Coyote tracks flowering shrubs on the dune fields in front of the Sangre de Cristo Mountains, Great Sand Dunes National Monument, Colorado

Tim Fitzharris / Indian Paintbrush (Castilleja coccinea) blooming, Texas

Tim Fitzharris / Annual Coreopsis (Coreopsis tinctoria) Texas Bluebonnet (Lupinus subcarnosus) and Drummond's Phlox (Phlox drummondii), Fort Parker State Park, Texas

Tim Fitzharris / Rhododendron (Rhododendron sp) blossoming at Mabry Mill, a restored sawmill and popular tourist destination run by the National Park Service, Blue Ridge Parkway, Virginia

Tim Fitzharris / Common Sunflower (Helianthus annuus) cluster and Temple of the Sun, Capitol Reef National Park, Utah

Jim Brandenburg / Water Lily (Nymphaea sp) on pond, Boundary Waters Canoe Area Wilderness, Minnesota

Tim Fitzharris / California Poppy (Eschscholzia californica) and Desert Bluebells (Mersensia sp) carpeting a spring hillside, California

Tim Fitzharris / Sand Bluebonnet (Lupinus subcarnosus) and Indian Paintbrush (Castilleja miniata) flowers in bloom, Hill Country, Texas

Tim Fitzharris / California Poppy (Eschscholzia californica) and Desert Bluebells (Mersensia sp) carpeting a spring hillside, California

Tim Fitzharris / California Poppy (Eschscholzia californica) and Desert Bluebells (Mersensia sp) carpeting a spring hillside, California

Tim Fitzharris / Paintbrush (Castilleja sp) and Bulbous Barley (Hordeum murinum), Hill Country, Texas

Tim Fitzharris / Sand Bluebonnet (Lupinus subcarnosus) and Indian Paintbrush (Castilleja miniata) flowers in bloom, Hill Country, Texas

Tim Fitzharris / Sand Bluebonnet (Lupinus subcarnosus) and Prickly Pear cactus (Opuntia sp), Hill Country, Texas

Shin Yoshino / Fireweed (Chamerion angustifolium) flowers in bloom around fire scorched trees, Yellowstone National Park, Wyoming

Tim Fitzharris / Mitten Rock with autumn colored cottonwoods and blooming desert shrubs, New Mexico

Tom Vezo / Northern Parula (Parula americana) male singing in blooming tree, Long Island, New York

Yva Momatiuk & John Eastcott / Indian Paintbrush (Castilleja attenuata) in bloom, close-up, Hill Country, Texas

Yva Momatiuk & John Eastcott / Indian Paintbrush (Castilleja attenuata) in bloom, close-up, Hill Country, Texas

Yva Momatiuk & John Eastcott / Indian Paintbrush (Castilleja attenuata) in bloom, close-up, Hill Country, Texas

Tom Vezo / Magnolia Warbler (Setophaga magnolia) perching in blossoming tree, Long Island, New York

Tom Vezo / Cape May Warbler (Setophaga tigrina) perching in flowering Geigertree (Cordia sebestena), Dry Tortugas, Florida

Michael & Patricia Fogden / Soaptree Yucca (Yucca elata) flowering on gypsum dunes, White Sands National Park, New Mexico

Tim Fitzharris / California Poppy (Eschscholzia californica), Eriophyllum (Eriophyllum sp) and Desert Hyacinth flowers, Portal Ridge, California

Tim Fitzharris / Lupine (Lupinus sp) in meadow at West Beach, Indiana Dunes National Lakeshore, Indiana

Tim Fitzharris / Lupine (Lupinus sp) in meadow at West Beach, Indiana Dunes National Lakeshore, Indiana

Tim Fitzharris / Teddy Bear Cholla (Cylindropuntia bigelovii) under stormy skies, Joshua Tree National Park, California

Tim Fitzharris / California Poppy (Eschscholzia californica) and Lupine (Lupinus sp) flowers in bloom, Tehachapi Mountains, California

Jim Brandenburg / Thickspike Gayfeather (Liatris pycnostachya) blooming in prairie, Iowa

Jim Brandenburg / Sunflower (Helianthus petiolaris) closely related to the Common Sunflower, South Dakota

Jim Brandenburg / Dogberry (Cornus sanguinea) trees in bloom, Great Smoky Mountains National Park, North Carolina

Tim Fitzharris / Opuntia (Opuntia sp) cactus blooming, Tierra Amarilla, New Mexico

Kevin Schafer / Kousa Dogwood (Cornus kousa) blooming in spring, Seattle, Washington

Tim Fitzharris / California Poppy (Eschscholzia californica) and Desert Yellow Fleabane (Erigeron linearis) flowers in spring bloom, Diamond Valley Lake, California

Tim Fitzharris / California Poppy (Eschscholzia californica) and Desert Bluebell (Phacelia campanularia) flowers in spring bloom, Chino Hills State Park, California

Tim Fitzharris / California Poppy (Eschscholzia californica) flowers in spring bloom, Lake Elsinore, California

Tim Fitzharris / California Poppy (Eschscholzia californica) flowers in spring bloom, Lake Elsinore, California

Steve Gettle / Large-flowered Trillium (Trillium grandiflorum), Great Smoky Mountains National Park, Tennessee

Steve Gettle / Large-flowered Trillium (Trillium grandiflorum), Great Smoky Mountains National Park, Tennessee

Tim Fitzharris / Lupine (Lupinus sp), Indiana Dunes National Lakeshore, Indiana

Tom Vezo / Evening Primrose (Oenothera sp) flowers in desert, Joshua Tree National Park, California

Jim Brandenburg / Iris (Iris sp) flowers, Minnesota

Larry Minden / Blooming cactus with scarlet flowers, Wah Wah Mountains, Utah

Tim Fitzharris / Palo Verde (Cercidium sp) blooming, Joshua Tree National Park, California

Tim Fitzharris / Phacelia (Phacelia sp) and Hillside Daisy (Monolopia lanceolata) flowers, superbloom, Temblor Range, Carrizo Plain National Monument, California

Tim Fitzharris / Cholla Cactus (Cylindropuntia sp) in bloom, Tierra Amarilla, New Mexico