In Memory of Bob Thorne

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In Memory of Robert Folger "Bob" Thorne 

Professor emeritus of Botany (Claremont Graduate University Department of Botany at Rancho Santa Ana Botanic Garden) and curator emeritus of the herbarium at RSABG, Bob Thorne peacefully passed away on Tuesday, March 24, 2015 in his residence at Oak Tree Lodge, Mt. San Antonio Gardens. He was 94.

Dr. Thorne was born on July 13, 1920 in Spring Lake, New Jersey. Up through his high school years, he lived in Gulfport and St. Petersburg, Florida. He graduated summa cum laude in 1941 from Dartmouth College and earned his M.S. degree in economic botany from Cornell University in 1942. The advent of World War II imposed a hiatus to his graduate studies while Bob served in the Army Air Force—flying 40 missions as chief navigator aboard a Consolidated B-24 Liberator. A favorite story that he loved to tell was about being shot down over the Adriatic Sea. As he parachuted near the water—aquatic plants being of keen interest to him—he observed to his delight a species that he had not seen before. Following WW II, Bob completed his Ph.D. at Cornell (1949). His academic career began at the University of Iowa, where he advanced from assistant to full professor (1949–1962). An offer from Rancho Santa Ana Botanic Garden brought Dr. Thorne to Claremont, where he served as taxonomist and professor, as well as curator of the RSABG herbarium (RSA-POM). Upon retirement, he was named professor emeritus by CGU and Pomona College, as well as RSABG taxonomist and curator emeritus of the herbarium.

Over the course of his long career, Dr. Thorne was recognized with many awards including a Fulbright Research Scholarship (1959-1960), Botanical Society of America Merit Award (1996), and Southern California Botanists Lifetime Achievement Award (1999). In 2001, he received the prestigious Asa Gray Award from the American Society of Plant Taxonomists. Among colleagues who wrote to support his nomination for the Asa Gray Award, Dr. Peter Raven (now president emeritus, Missouri Botanical Garden) wrote, “Bob is an incredible scholar and a marvelous human being! … a world leader in the study of plant geography, phylogeny, and floristics … under his guidance, the herbarium grew and prospered, becoming one of the outstanding repositories of plants from the western United States and elsewhere.” In 2006, Dr. Thorne was recognized as a Distinguished Fellow of the Botanical Society of America—the highest honor that BSA bestows.

Until a few years ago, Bob regularly worked in his office at RSABG resulting in the publication of “An updated classification of the class Magnoliopsida” (Thorne & Reveal, Botanical Review, 2007) and “Vascular plants of the high Sierra San Pedro Mártir, Baja California, Mexico” (Thorne, Moran, & Minnich, Aliso, 2010).

In addition to his plant collections for the herbarium (over 60,000 specimens added), he was a serious collector of postage stamps, amassing a large collection that emphasized stamps of plants and birds.

His colleagues in the plant sciences and many friends will sorely miss Bob Thorne but, by virtue of the scientific knowledge that he contributed, his legacy will long endure.

Dr. Thorne is survived by his wife of 68 years, Mae Zukel Thorne, his daughter Linda Thorne and her husband Tony Petrella, and his nephew Doug Fredericks and wife Karen, great niece Colby Poppleton and niece Kathie Fredericks, and two cherished great-grandchildren Katie and Zoe Petrella.

A Celebration of Life will be held at Rancho Santa Ana Botanic Garden on Saturday, July 11, at 5 p.m. In lieu of flowers, the family requests that Bob Thorne’s life be honored by donations to Rancho Santa Ana Botanic Garden to be used to advance the kind of scientific work to which he dedicated his professional life. 


See Also:

In Memoriam about Dr. Thorne posted at the American Society of Plant Taxonomists.


Botanical Beauties: Seasonal Highlights

The Garden Through the Seasons

No matter when you visit Rancho Santa Ana Botanic Garden, there is always something to see.

With more than 6,000 kinds of native plants, California has the richest flora of any state in the continental United States. Rancho Santa Ana Botanic Garden is dedicated to the collection, cultivation, study and display of native California plants. A number of flowers as well as interesting fruits and seeds can only be seen at particular times of the year.

Choose a season below to help you navigate 86 acres of native botanical beauty of California to see a sampling of the showiest seasonal displays in the Garden.



See the Garden anytime on our Facebook page.

The cool, rainy winter season allows plants to put on fresh green coats. Winter rains begin the period of active growth and flowering. There is a great diversity and abundance of birds in the Garden year round, but especially in the winter. Check in at the admission kiosk for tips on which of our feathered friends you may see during your visit.

Look for Encelia californica (bush sunflower), which can be found throughout Garden; Acer macrophyllum (big leaf maple) found on the slope west of Fay's Wildflower Meadow; and Ribes aureum (golden currant) in the Communities. Heteromeles arbutifolia toyon berries throughout the Garden, Roger's Red grape in Cultivar Garden, Russian River monardella in Cultivar Garden, Celtis reticulata western hackberry in Desert Garden in January. Many gooseberries and currants, both in the genus Ribes, bloom in February. Gooseberries, such as the fuchsia flowering gooseberry (R. speciousum), have spines. Currants include the golden currant (R. aureum), chaparral currant (R. malvaceum), and the pink flowering currant (R. sanguineum). All have edible berries and grow well in gardens with some shade and year around water. These are deciduous, lossing their leaves in summer. Catalina perfume (R. viburnifolium) is an unusual currant that is evergreen, has a delightful aroma, and does well as a groundcover beneath coast live oaks (Quercus agrifolia).


Manzanita (Arctostaphylos ssp.)

Winter is the time of the manzanita and the Garden boasts a large collection, which bloom late November through early March. See the delicate urn-shaped flowers in the California Plant Communities and throughout the Garden. There is a great variety of manzanitas ranging from tidy groundcovers to large multi-stemmed trees. Lester Rowntree manzanita is a large, broad shrub with gray-green leaves, and pink stems and flowers. If you have heavy garden soil consider growing this plant. Another dependable garden manzanita, Howard McMinn, is smaller and more upright than Lester Rowntree. Its profusion of white flowers, in early spring, contrast nicely with green foliage and cinnamon-colored bark. The following plants provide beautiful winter displays. Arctostaphylos 'Canyon Blush (Canyon Blush manzanita) located on Indian Hill Mesa south of the Cultivar Garden; Arctostaphylos 'Canyon Blush' (Canyon Blush manzanita) located on Indian Hill Mesa; Arctostaphylos refugioensis (Refugio manzanita) located in the California Plant Communities, Arctostaphylos 'Lester Rowntree' (Lester Rowntree manzanita) located in the Cultivar Garden; Arctostaphylos pungens (Mexican manzanita) located south of Fay's Wildflower Meadow; Arctostaphylos pungens (Mexican manzanita).




Dutchman’s Pipe (Aristolochia californica)

Aristolochia is an interesting, semi-evergreen vine that always attracts attention with its masses of pipe-shaped flowers producing in late winter and early spring. This vine is found in the Garden climbing along slopes and over shrubs. Visitors are first attracted to the large, fuzzy arrow-shaped leaves, then to the odd shaped flowers. Run your fingers along the stem and leaves of this twining plant and feel the fine, silky hairs. Six-legged visitors are also attracted to this plant. The brownish to greenish-purple flowers are pollinated by fungus gnats, that get trapped inside the flowers, and the leaves are eaten by larvae of the western pipevine swallowtail butterfly (Battus philenor).




Big Leaf Mistletoe (Phoradendron macrophyllum)

The name, Phoradendron, comes from two Greek words signifying thief of a tree. Indeed mistletoe is a parasitic plant growing on trees or shrubs, absorbing water and food from the sap of the host plant. The clumps of the evergreen mistletoe festooning trees in the Garden are most conspicuous in winter when leaves have dropped from the tee hosts. Big leaf mistletoe is chiefly parasitic on western sycamore, Platanus racemosa but also may be found on cotton wood (Populu spp.), alder (Alnus spp.), ash (Fraxinus spp.) and walnut (Juglans spp.)





Catalina Crossosoma (Crossosoma californicum)

Crossosoma is an uncommon and botanically interesting plant found on dry, rocky slopes and in canyons on San Clemente, Santa Catalina and Guadalupe Islands and on the Palos Verdes Peninsula. The plants become dormant during the summer months and the dead leaves remain hanging on the shrubs until the advent of the autumn rains, when they are shed and the plants suddenly become covered with bright green leaves and soon after with apple-blossom like flowers. The fruit is unusual looking; a cluster of 2-9 drooping, dry vessels each about 1 inch long and terminating in a curved or hooked beak.




Silk Tassel Bush (Garrya elliptica)

Garrya is a horticulturally significant plant, grown for its drought tolerance and attractive, pendulous flowers. It is an evergreen shrub with male and female flowers borne in catkin-like clusters on different plants. Silk tassel is found from Ventura County north to Oregon and on Santa Cruz Island on dry slopes and ridges in the outer coast ranges at elevations below 2,000 feet where it is a member of several plant communities from the missed evergreen forest to chaparral. It is nowhere in abundant and usually occurs in small groups or an isolated shrubs.




San Clemente Island Bush Mallow (Malacothamnus clementinus)

This is an endangered plant in California. Occurring in only a few localities on San Clemente Island it is threatened by navy activities and grazing b feral animals. This slender-stemmed, erect shrub forms colonies by underground runners. The foliage of this plant is favored by every kind of herbivore. The hairy, bright green leaves are round in outline with three to five lobes. The flowers, arranged in spike-like clusters, are white to pale pink in color. A striking characteristic of its plant family (Malvaceae mallow family) can be seen in the flowers. The stamens are fused into a column around the pistil as in the very familiar hibiscus. Peer into these flowers to observe that character.




Mission Manzanita (Xylococcus bicolor)

Mission Manzanita is similar to the true manzanita (Arctostaphylos spp.) in general appearance, but can be easily distinguished by its leaves and fruits. The leaves of Xylococcus are leathery and brittle with margins that are rolled under. The upper surface of the leaf is dark green; the lower surface densely hairy. The fruits are berry-like, dry and become maroon-red or black when mature. Like the manzanita, Xylcoccus blooms during the winter months and has clusters of urn shaped, white, yellow or pinkish flowers. Mission Manzanita is found on dry sloes in scattered localities from near the coast in Los Angeles County south to northwestern Baja California, usually at elevations below 2,000 feet where it is a member of the coastal chaparral community. It is also found on Santa Catalina Island.




American Dogwood (Cornus sericea ssp. sericea note: formerly C. stolonifera)

American dogwood is a large spreading shrub 6 to 30 feet tall, often rooting where the branches touch moist ground. The arching stems are a distinctive red-purple color. The leaves are arranged opposite one another along the stem and have four to seven prominent veins that form thin latex threads when broken. Individual flowers are inconspicuous but are arranged in large, noticeable flat-topped clusters. They bloom from May to July then develop into small round, whitish stone fruits. American dogwood occurs in moist places below 9,000 feet.




White Alder (Alnus rhombifolia)

White alder is the only member of birch family found in Southern California. It is widely distributed along rivers and permanent streams. The bark of young trees is a smooth steel gray color that becomes darker and broken into irregular plates on old trees. The male flowers are arranged in 2 to 4 inch pendulous catkins at the ends of the branchlets. Female flowers are distinctive little woody catkins that look like miniature cones of conifers. The seeds are shed from this cone in the fall and winter to the apparent delight of flocks of grosbeaks and finches who gobble-up the tiny seeds during winter months.








Fuchsia-flowered Gooseberry (Ribes speciosum)

The gooseberries are a distinctive group, with their spiny branches and rounded to deeply lobed leaves. Our most interesting species is the fuchsia-flowered gooseberry, which has abundant bright red pendulous flowers that line the arching or sometimes horizontal stems of the plant for a length of up to several feet. The stamens are twice as long as the flower and are exserted from the floral tube. The fruit is sticky and exceedingly prickly, but like all our prickly gooseberries they are eminently edible. Fuchsia-flowered gooseberry is a member of the coastal sage scrub and chaparral communities and is common throughout Southern California. It blooms from February to April and is an important nectar plant for hummingbirds in the winter season.




Wild Cucumber, Man Root (Marah macrocarpus)

Wild cucumber is a trailing vine from a huge, fleshy root with long, stalked leaves palmately lobed and up to 4 inches across. The creamy white flowers are interesting as some are male and some are female on the same plant just like other members of the cucumber family (melons, squash, etc.) The male glowers appear on the stems in groups of five to 20 with the stamens exposed and noticeable. At the base of this stem may be one female flower with a fat, little ovary that develops into a large, egg-shaped fruit with long, bright green prickles that turn hard and spiny as the fruit dries. The flowers of this vine are among the first flowers to bloom often starting in January and continuing to June. Because of its large root, it is one of the first plants to reappear after a fire. The long green stems spreading over the blackened soil are particularly noticeable.




Chaparral Currant (Ribes malvaceum)

Ribes malvaceum is a deciduous member of the chaparral community. The pink flowers are in drooping clusters and appear in the early winter often before the first leaves. It is a refreshing burst of color in the chaparral after the long period of summer drought and dormancy. The flowers are an important source of winter nectar for resident hummingbirds. The lobed maple-like leaves of this species are dark green and roughened above, paler below. The fruit is a dark purple to black smooth berry. The branchlet, leaves, flower clusters and fruits of this plant have glandular, bristly hairs that make the plant sticky to the touch and give this plant its distinctive aroma.




California Bay (Umbellularia californica)

The California bay, an evergreen tree, can reach a height of 90 feet. The lance-shaped leaves with smooth margins are thick, leathery and 3 to 5 inches long. When crushed, the leaves emit a pungent odor suggesting camphor or bay, which serves as a positive identifying characteristic. Leaves are often used for flavor in cooking, but are about twice as strong as the European bay (Laurus nobilis). The clusters of yellow-green flowers, appearing from December through May, have an agreeably sweet fragrance. The fruits are fleshy and green and look like small avocados (a relative of this plant).




In the spring, the Garden is full of color as California poppies (Eschscholzia californica), California lilacs (Ceanothus sp.) and salvias burst into bloom. Wind your way through Fay’s Wildflower Meadow on the one-of-a-kind stone-tiled rattlesnake path. The riots of color throughout the Garden attract butterflies and hummingbirds. Spring is the peak season for flowers of all kinds. Wildflowers abound in Fay’s Wildflower Meadow, irises brighten the Indian Hill Mesa, vibrant cactus flowers illuminate the desert area in the East Alluvial Garden, and wild lilacs softly scent the air throughout.

The Butterfly Pavillion is open late spring through summer. The pavilion combines science education and interactive fun for visitors of all ages. Read more about the RSABG Butterfly Pavilion here.

Summer and autumn months provide a more subtle color and texture in the Garden as native fruit and seeds ripen. The dry summer months are a time of dormancy for many plants. Visit during our concert series Garden Groove in June and July to enjoy a cool evening walk and great music in the Garden. 

Summer is quieter but the pink flowers of the desert willows and the bright yellow of the Palo Verde in the Cultivar Garden add colorful highlights to the tawny browns, soft grays and greens of the grasses, shrubs, and trees. Visit the Container Garden for new ideas on growing natives in pots.

As the hot months give way to cooler autumn days, plants begin to waken after their summer slumber. Fall is the time to plant California native plants. A visit to the Garden may provide inspiration for your inner landscape designer. It is the time of anticipated seasonal rains and the start of the planting season. Attend the annual Fall Planting Festival on the first weekend of November at Grow Native Nursery Claremont to purchase old favorites and exciting new native plants.


California Buckeye (Aesculus californica)

The California buckeye is native to the Foothill Woodland commmunity inhabiting the dry slopes and canyons. One of California's most unusual and picturesque trees, the Aesculus californica is small, deciduous and multi-stemmed. It grows to 15 to 30 feet tall with broad, rounded crown and smooth gray-white bark. Showy, foot-long spikes of creamy white flowers cover the trees in spring and are fragrant. As drought stress increases in the summer, the foliage becomes brown and heat-crumpled. The branches are leafless by early fall, revealing conspicuous pear-shaped pods containing large, shiny, chestnut-colored seeds.



Madrone (Arbutus menziesii)

Madrone is considered by many to be the most handsome broadleaf, evergreen native tree. It has a wide distribution with scattered stands found in the peninsular ranges in Southern California and extending north through the foothills of the Sierra Mountains and along the coastal ranges to British Columbia. It is most common in California's north coast ranges where it grows with douglas fir, tan oak and black oak on mountain ranges, slopes and valleys. The madrone is a picturesque tree with smooth, terra cotta colored bark, glossy, burnished foliage, large clusters of fragrant urn-shaped white flowers and brilliant orange-red berry-like fruits, which ripen in the late fall.



Refugio Manzanita (Arctostaphylos refugioensis)

This rare manzanita occurs in a botanically complex region where the South Coast and Transverse Ranges converge north of Santa Barbara. Refugio manzanita has strongly overlapping leaves which clasp the twigs and stems that are densely clothed with glad-tipped bristles. In its natural habitat, Refugio manzanita blooms from Decmeber through March, but in cultivation this species is the earliest flowering of the manzanitas in the Garden. Blossoms can appears as early as October.



California Fuchsia (Epilobium)

California fuchsias are slightly woody, perennial herbs that grow to 1 to 3 feet high. There are many named varieties in the Cultivar Garden, displaying varied growth habits, foliage and flower color. The striking feature of this plant is the showy, tubular flower. The four petals and the four-cleft sepal cup are typically scarlet, but some cultivars are white or pink. Two common species in Southern California, Epilobium californica and Epilobium canum, bloom in dry portions of Coastal Sage Scrub, Chaparral, Oak Woodland and the Yellow Pine Forest plant communities from July through November. California fuchsias are an important nectar plant for hummingbirds during late summer. It does well in California gardens and is readily available from native plant nurseries.



St. Catherine's Lace (Eriogonum giganteum)

This medium-size shrub is native to San Clemente and Santa Catalina Islands where it is a member of the Coastal Sage Scrub communities. Large, flat-topped clusters of white flowers develop in late spring on stalks that branch well above the foliage. The flowers fade to a russet-brown in the fall and are quite showy against the silvery-gray leaves. Eriogonum giganteum performs well in cultivation, in both coastal and inland regions, and is frequently used in landscapes and gardens.



Four-needled Pinyon, Parry Pinyon (Pinus quadrifolia)

Pinus quadrifolia has needles that are four to a bundle. That number can be variable however, and you may find trees with some bundles of three or five needles. The pinyon is an extremely handsome, small tree with a pleasing pyramidal form. The short needles are pale blueish-green on top and white on the under surface. It is found in scattered localities on dry slopes bordering the Colorado Desert, from the Santa Rosa and San Jacinto Moutnatins to Baja California. The pinyon nuts of this species as well as Pinus monophylla, the singleleaf pinyon, were a staple food item for many groups of Native Americans.



Toyon, California Holly (Heteromeles arbutifolia)

Toyon is a large, handsome shrub or small tree with evergreen, leathery, saw-toothed edged leaes. The showy clusters of small, white flowers in summer mature to bunches of rich, red berries in late fall and winter. The berries are significat source of winter food for birds and other wildlife. Look for a lot of variation in the color and size of the berries as you walk through the Garden. Two cultivate varieties of toyon having yellow to gold berry color are 'Claremont' and 'Davis Gold.' Toyon is one of the most widely cultivate California natives because it ofers both attractive foliage and fruit, and shows a wide tolerance for different soils, exposure and moisture conditions.



Chuparosa, California Beloperone (Justicia californica, Beloperone)

Chuparosa is a rounded, twiggy desert shrub with numerous intertwined greenish branches. The leaves are small and drop off as soon as the plant is drought stressed. A striking feature of chuparosa is the orange-red, tubular blossom. The flowers are grouped in terminal clusters, a perfect vantage point for visiting hummingbirds that frequent this plant during its long fall and winter flowering season. A native of sandy washes and bajadas of the Sonoran Desert, chuparosa is well adpated to hot, dry climates and is recommended for gardeners who want to attract hummingbirds with a natural food source.



Catalina Cherry (Prunus lyonii)

Catalina Cherry is native to Santa Catalina, San Clemente, Santa Rosa and Santa Cruz islands off the coast of Southern California. It grows in the Island Chaparral plant community and reaches its largest size (35 to 40 feet) in canyons and protected areas where greater moisture and deeper soils occur. This species has evergreen, glossy dark green leaves that are 3 to 5 inches long. Showy, creamy-white flowers appears in late spring to early fall.




Sugarbush (Rhus ovata)

Sugarbush is an erect, medium-size shrub with distinct reddish twigs and thick, waxy leathery leaves. A key characteristics of this plant that distringuishes it from its Rhus relatives is that the leaf blades fold sharply upward at the midrib resembling a taco shell. The dense, terminal clusters of tiny pinkish-white flowers give way to sticky, sugary, russet-colored fruits in late summer and early fall. The evergreen foliage and tolerance for various soil and climate conditions makes sugarbush a desirable ornamental for heges and screens.



Woolly Blue Curls (Trichostema lanatum)

The woolly blue curls plant is a member of the chaparral plant community. It can be difficult to propagate and is frequently finicky in cultivation. To the amazement of RSABG horticulture staff, woolly blue curls performs exceddingly well in the Indian Hill Mesa soil and flowers intermittently year round. The attractive flowers are an elaborate two-lipped, blue or purple blossom tightly packed along the upper stem. The whole flower cluster is densely cothed in purple wool-like fibers. Strongly aromatic, woolly blue curls are a member of the mint family.



California Wild Grape (Vitis californica, 'Roger's Red')

The California wild grape is a robust vine, closely resembling (and frquently a rootstock for) its cultivated cousin the wine grape. Growing along streamsides and springs, the wild grape is readily recognized by its trailing habit as it attaches to other plants with coiling tendrils. The purple fruits are small but taty and can be eaten fresh or dried. 'Roger's Red' is a cultivated variety selected for its brilliant scarlet autumn foliage.

Western Gray Squirrel

Critters in the Garden

Carol Lerew
RSABG Volunteer, Nature Interpreter

A delight to visitors of all ages, the tree squirrels at Rancho Santa Ana Botanic Garden provide entertainment as well as insights into nature. School children are often diverted from theme-lead tours by the squirrel’s acorn-hoarding activities or breathtaking treetop acrobatics. Nature Interpreters take advantage of these teachable moments to lead discussions about the habits and habitats of these engaging creatures.