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MDIA Turns 50! Steve Smith, MDIA President 1974 - 2024 January 1, 2024 The Mount Diablo Interpretive Association is celebrating a huge milestone this year, our 50th Anniversary! MDIA was the brainchild of Sam Smoker, Executive Director of the Lindsay Museum in Walnut Creek, who formulated a vision of an interpretive association that would supplement, in a significant way, the work of the small staff of rangers at the ever-expanding Mount Diablo State Park. Smoker recognized the need for a wider public appreciation of this great natural treasure that exists within an area of rapid urban expansion and concurrent loss of the original environment. The task was interpretive; the key was education. A meeting convened on the proverbial dark and stormy night of January 30, 1974 in Smoker's living room. Among those present were Mary Bowerman, founder of Save Mount Diablo and preeminent botanist; Frank Valle-Riestra, a scientist with an interest in natural history; Ron Edwards, a wildlife expert from the Lindsay Museum; Phil Gordon, biology teacher, and ornithologist associated with the Audubon Society; Beverly Clemson, Director of the Shadelands Ranch Historical Museum; Howard Knight, Professor of Biological Sciences at Diablo Valley College; Betty Zilen, retired Mount Diablo School District science supervisor; and Ed Earl, Superintendent of Mount Diablo State Park. MDIA continues its long-standing mission of Preservation through Education and has remained an all-volunteer non-profit cooperating association benefiting Mount Diablo State Park. BACK TO LIST

Wildflower Mount Diablo Douglas' Monardella Scientific Name: Monardella douglasii Family: Lamiaceae (Mint Family) Blooms: Jun Color: Blue-Purple Annual herb Native, endemic to California Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Kevin Hintsa

Wildflower Mount Diablo Bird's Foot Trefoil Scientific Name: Lotus corniculatus Family: Fabaceae (Legume Family) Blooms: May-Jul Color: Yellow-Orange Perennial herb Introduced Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Daniel Fitzgerald

Live Oak Campground Map

Mylitta Crescent Butterfly by Dan Sandri These orange beauties love their jam! April 5, 2025 Mylitta Crescent, by Dan Sandri Are you seeing little, orange butterflies, smaller than Tortoiseshell butterflies, moving up and down the trail? They might well be Mylitta Crescents, an abundant Spring, Summer and even Fall butterfly that owes its extended seasonal success, in large part, to non-native thistles. The Mylitta Crescent is orange, with fine to thicker black markings – they are quite variable in lightness/darkness. The tips of the clubs of their antennae are orange. Before the import of European thistle species, Mylitta Crescent adults had a Spring season, as that is when our native Circium thistles (including C. douglasii and C. occidentale ) grow. But now, when the native annual thistles dry up, the butterflies can switch over to laying eggs on non-natives like Bull Thistle (Cirsium vulgare ) and others, which are able to grow through the Summer and are also found in disturbed areas (expanding Mylitta’s range too). Overall, they range from Southern British Columbia well into Mexico, and east to Eastern Colorado and Wyoming. On Mount Diablo, the butterfly can be seen as early as late February and as late as mid-October. Male butterflies perch on the ground, or on plants, and move about searching for females near thistle plants. Females lay eggs on the underside of thistle leaves, and there can be multiple broods each year. The last generation of caterpillars will hibernate as partially-grown caterpillars. Caterpillars are black, with spines and minimal white markings. So, when you see these little orange beauties, remember that thistles are their jam! Explore more butterflies at our Butterfly Guide: https://www.mdia.org/butterfly-guide Mylitta Crescent, Male on Fiddleneck Cobweb thistle, Circium occidentale (native) Bull thistle by Ken-Ichi Ueda (imported) BACK TO LIST

Visitor Center Status - Mount Diablo Summit Visitor Center Open 7 days/week Hours: 9:30 AM – 4:30 PM One way foot traffic through the Visitor Center to minimize crowding. Enter at ground level and exit on second level. Lower floor (sales), Second floor (exhibit room) and Observatory deck will be open. Face coverings are required for all indoors regardless of vaccination status. Mitchell Canyon Visitor Center Open for outdoor operations on weekends and some holidays Hours: 8:00 AM - 4:00 PM The interior remains closed. Operations including sales are currently being done outdoors only. Mitchell Canyon Visitor Center BACK TO LIST

Tassajara Creek Hike by Steve Smith Reprinted from the MDIA E-Newsletter June 2024 June 1, 2024 Stephen Smith In the dog days of summer, it can sometimes be challenging to find a suitable hike on Mount Diablo. Tassajara Creek trail is a little out-of-the-way for most, off the beaten path, but partially shaded. Please note that the first and last ½ mile of this hike is along paved Finley Road until the new trailhead is built further up. Some consolation is offered in the pastures of horses, goats, geese, ponies and a llama along the way as well as the historic one-room Tassajara Schoolhouse on the drive there. This remote area of the park has many wonderful features including grand vistas of the Tassajara and Livermore Valleys as well as Cave Rocks and Cave Point. Rolling hills lead to a sheltered canyon at the headwaters of Tassajara Creek. Park on the shoulder of Finley Road and continue on foot for ½ mile to the entrance. You will first hike into EBRPD’s Morgan Territory up Old Finley Road. A left on Riggs Canyon Road will take you into MDSP. Continue for ¾ mile, Riggs Canyon will make a sharp left and begin climbing. At this bend look for an unsigned trail off to the right which will lead you 25 yards to Tassajara Creek. Turn left as you wind along the creek in the shaded canyon for 1 mile. Once you break out into the sunlight again, stop at the picnic table overlooking Bob’s Pond. Continue around the trail loop, now in full sun, as you wind along the base of Windy Point and Highland Ridge. At trail’s end, turn right on Highland Ridge Road, at the fork, stay right back onto Old Finley Road. Take this trail all the way back to the trailhead. Their are numerous side trips you can take including the Amphitheater Trail loop. This adventure takes you 8 miles with 1100 feet of climbing and is guaranteed to offer privacy, particularly on weekdays. Come early (or late) on weekends for parking. For directions to Finley Road trailhead, click here . For a route map click here . If you would like a .gpx file to help you navigate please download it here . Morgan Territory Tassajara Creek BACK TO LIST

Wildflower Mount Diablo Dudleya, Rock Lettuce, Stonecrop Scientific Name: Dudleya cymosa Family: Crassulaceae (Stonecrop Family) Blooms: May - Jun Color: White Perennial herb Native, endemic to California White form is shown here. Flowers are typically a vibrant orange, yellow or pink. Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Kevin Hintsa

Wildflower Mount Diablo Pearly Everlasting Scientific Name: Anaphalis margaritacea Family: Asteraceae (Sunflower Family) Blooms: Jun - Aug Color: White Perennial herb Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Hank Fabian, iNaturalist

Wildflower Mount Diablo Glittering Vervain Scientific Name: Verbena gemmea Family: Verbenaceae Blooms: Color: Blue-Purple Perennial herb Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants

Wildflower Mount Diablo Golden Yarrow Scientific Name: Eriophyllum confertiflorum var. confertiflorum Family: Asteraceae (Sunflower Family) Blooms: May - Jun Color: Yellow-Orange Shrub Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Kevin Hintsa

Wildflower Mount Diablo Big Flower Agoseris Scientific Name: Agoseris grandiflora Family: Asteraceae (Sunflower Family) Blooms: Mar-May Color: Yellow-Orange Perennial herb Native Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Steven Beatty