Manzanitas: Early Bloomers

The timing of these earliest bloomers in California native flora is keyed to the seasonal migration of hummingbirds and the emergence of bumblebees and native bee species.

An Early Spring in the Garden

Bart O’Brien
RSABG Director of Special Projects

After this past summer’s heat, and the welcome arrival of significant early fall rains, many of the manzanitas (Arctostaphylos species) in the living collection at Rancho Santa Ana Botanic Garden have burst into bloom seemingly overnight. How does this happen so quickly in manzanitas and their close relatives (Xylococcus bicolor—mission manzanita and Ornithostaphylos oppositifolia—palo blanco)? It all comes down to a successful strategy of adaptation to our mediterranean climate – nearly all of these plants (yes, there are one or two exceptions) prepare to take full advantage of late fall and winter rains and pollinators by producing fully formed yet dormant inflorescences at the tips of their branches at the end of their spring growth cycle (you can tell that their growing season is over when their bark peels in late May or early June; this tells you that they have entered summer dormancy). These claw-like structures are called “nascent inflorescences” and that is indeed what they are—preformed, ready-to-go flower clusters just waiting for the cooler temperatures and rainfalls of late fall and early winter that triggers their rapid expansion into full bloom. The timing of these earliest bloomers in California native flora is keyed to the seasonal migration of hummingbirds and the emergence of bumblebees and native bee species.

Typically, here at RSABG, the first of the manzanitas to flower is the rare and endangered Refugio manzanita (A. refugioensis) from Santa Barbara County. Most years, these plants begin flowering in late October or November and are followed by a progression of different species and cultivars with the greatest number of plants usually blooming in January and February. The last manzanitas finish blooming sometime in March or early April. Another similarly diverse group of plants that has nearly the same blooming season are the currants and gooseberries (Ribes species). You will almost always see some chaparral currants (Ribes malvaceum) beginning to bloom in late October or November, too.

The production of nascent inflorescences in these three closely related plant genera is unique in California native flora—and this writer cannot think of any other example of this phenomena worldwide. All other plants produce stems, leaves, flowers, and fruits in comparatively slow to moderate progression. Manzanitas and their kin are great examples of plants rapidly responding to environmental cues.

How did this come about? I can speculate that the most widespread species, kinnikinnick (A. uva-ursi) is a plant that is found predominantly in cold arctic and alpine environments, and in fact its distribution is circumboreal. In such harsh conditions it is likely advantageous to the plant to be among the first to bloom in order to take full advantage of favorable pollinator and climatic conditions. Carrying that early-blooming characteristic to California’s more extreme Mediterranean climate (California has the longest dry season and the coldest winter temperatures of the world’s Mediterranean climate areas) would likely have the same advantages.

Particularly of note to those of us here at the Garden is the taxonomic importance of manzanita nascent inflorescences. From the time that California’s manzanitas were first discovered up until the late 1930s, botanists had a very hard time discerning the differences between species of manzanitas. They could see that there were many different kinds, but had great difficulty in characterizing this diversity. Alice Eastwood, Willis Jepson, Katherine and Townshend Brandegee, Marcus Jones and many others seem to have missed out on this, the key diagnostic feature of manzanitas. However, once Albert E. Wieslander described the importance of this characteristic in his 1939 paper (and coined the phrase “nascent inflorescence”), all students of the manzanitas quickly realized that this indeed was the main key to differentiate the incredible diversity of the group. (There are more taxa of manzanitas in California than there are of any other woody plant group). There’s more to this story – and how Jepson “stole” Wieslander’s concept (he called these structures “embryonic panicles”) and a number of his species—but that will have to wait.

To be continued...

Plant Communities and Climate in Southern California

We are accustomed to thinking of Southern California climate as mild, but it is really anything but mild from the perspective of the remarkable native plants.

Lucinda McDade
RSABG Interim Executive Director

The image that is conjured by summer may be a sure way to separate native Californians from those of us who are transplants from other parts of the U.S. In the regions of California that lie within the California Floristic Province (CFP), summers are dry, hillsides turn golden and look like home, and umbrellas can be safely left in the closet for months on end (and you are guaranteed to have to look very hard to find yours come the first rains of fall). People from elsewhere—at least in the early stages of their adjustment as transplants—speak of missing thunderstorms and describe the golden hillsides as brown and unattractive.

Summers in California are, as we know, warm (to hot!) and dry (in coastal areas the aridity is mitigated by fog, at least in the early summer), whereas winters are cool and moist. In fact, the transplants have the right to claim that theirs is the more typical understanding of summer in that areas that share the Mediterranean climate regime with California are extremely limited in area worldwide. Only about 2 percent of Earth’s total land surface shares this climate regime with us and these areas occur in only four other places: southwestern (and a bit of south central) Australia, central coastal Chile, the western Cape region of South Africa and, of course, the Mediterranean proper.

We are accustomed to thinking of our climate in Southern California as mild, but it is really anything but mild from the perspective of the remarkable native plants. The climate challenges them to be physiologically active (to grow, flower, produce fruits and seeds) during the cool winter and spring months when there is moisture to support these plant processes. Just when it warms up, it also dries up and, although temperatures would otherwise be conducive to plant growth, only the most deeply rooted (or riparian) plants are able to reach the water necessary to support such growth. Most California native plants thus go dormant: they complete their growth and reproduction for the season (or forever in the case of annual plants) and our hillsides turn golden. The plants must manage to survive for five to seven months with very little moisture (and quite a bit of heat depending upon location).

Despite this challenging climate and the very limited extent of Mediterranean climate zones worldwide, these regions are all associated with remarkable plant species diversity. About 20 percent of all flowering plant species on Earth occur on just 2 percent of the Earth’s surface in these five regions. One way to think about this is in terms of species ‘density’ or number of species per unit area of land. In continental areas that are of similar latitude but that do not have a Mediterranean climate, there are 1.5-3 thousand species per million square kilometers (for reference, the state of California is 424,000 square kilometers in area). In marked contrast, Mediterranean climate zone regions have approximately 12 thousand to more than 90 thousand species per million square kilometers (the remarkable Cape region of South Africa lays claim to this highest number). Thus, for example, the flora of California houses almost a third of all plant species in the U.S. even though it accounts for only about 5 percent of the nation’s land area.

High species diversity in Mediterranean climate zone areas is accompanied by two patterns that can put these floras in peril: high levels of (1) endemism and (2) rarity. Plants (and animals) are said to be endemic when they occur only in a specified and often small area. Thus, many of the plants that occur in the California Floristic Province occur only in this area and are often further restricted in range within it. Plants with a restricted range are almost by definition rare, at least compared to those with broader distributions, but they may also be rare even within their range. You will immediately realize that these patterns can make our plants vulnerable to extinction; in fact, nearly 1/3 of the native plant taxa of California are ranked by the California Native Plant Society as rare, threatened or endangered.

Another very interesting feature of Mediterranean climate zone regions is that the plant communities are convergent: they look alike. Thus, our chaparral looks very much like the maquis of the Mediterranean, the matorral of Chile, the fynbos of South Africa, and the kwongan of western Australia. This pattern of convergence continues to the level of traits of individual plants, particularly as regards leaves, which are usually evergreen and tough no doubt as adaptations to surviving hot, dry summers (sclerophyllous is the technical term; think about our manzanitas). Interestingly, these patterns are true despite the fact that the plants of these five areas are largely unrelated taxonomically. The remarkable proteas of South Africa and Australia are not native here although the fact that many perform well here in cultivation is testament to our shared climatic regimes! Similarly, you will not find manzanitas in South Africa (except in cultivation) but you will find many many species of the genus Erica which belong to the same plant family, Ericaceae.

Those of you who have replaced your lawns with native plants may have experienced the disdain of neighbors when your landscape goes dormant in the summer. In fact, this is one of the major challenges that we face in winning acceptance for native plants in home landscapes: many do not look all that great during the hot, dry summer months. Considering that they will need very little to no water and will very rapidly return to lush beauty with the first rains of fall, I would suggest that it is asking too much of them to look good all summer too. Armed with this knowledge of the challenges that California native plants face in growing and surviving our mild-for-us but tough-for-them climate, at least you can explain what’s going on to you neighbors! These plants deserve our respect and admiration and a place in our landscapes!

Kangaroo Rat

Critters in the Garden

Carol Lerew
RSABG Volunteer, Nature Interpreter

Hopping Down the Desert Trail

If you’ve spent time in the desert you may have observed a small curious-looking creature hopping among the cactus. At first glance it sort of resembled a mouse on a pogo stick or maybe a rat with a caffeine high.

The kangaroo rat, genus Dipodomys, is a small rodent native to North America. Its large hind legs enable it to hop similar to the kangaroo, for which it is named. It is in no way related to that larger animal. Rather, it is related to the pocket mouse family, which includes kangaroo mice and pocket mice. The kangaroo rat inhabits many semi-arid to arid areas of California. One of our long-time volunteers reports a Google site listing 22 endemic North American species, many of which occur only in California! Most of those species are federally listed as special concern or endangered. Three are thought to be extinct. So far as is known, no kangaroo rats have ever been sighted by staff or volunteers at RSABG.

A pale yellow-buff to grey, depending on habitat, and with a white underbelly, the kangaroo rat can reach up to 14 inches in length and 8 inches tall. Many species are much smaller. Its large head is topped with very large ear capsules. The tail is longer than the body and ends with a dusky tufted tip.

Kangaroo rats are able to go their entire lives without drinking a drop of water. They derive enough water from their metabolism and food. Various kinds of seeds are diet mainstays although other vegetation as well as insects is eaten on occasion. Fur-lined cheek pouches are used for storing food during foraging. Food is gathered at night and stored in burrows.

Kangaroo rats live in complex burrow systems where separate chambers are used for specific purposes like sleeping, living and food storage. The burrows may extend as much as three or four feet underground and have multiple entrances. Desert burrows are evidenced by mounds found in the loose sandy soil under creosote and salt bushes. They provide protection from the harsh environment as well as from predators. However, coyotes often outsmart the kangaroo rats by digging them out! When the outside temperature is too hot, a kangaroo rat stays in its cool, humid burrow and leaves it only at night. When sleeping, it buries its nose in its fur to reduce loss of moisture.

Solitary animals, the males protect their territory by thumping opponents with their hind legs—sort of a miniature kickboxing match. In spite of who wins, the females tend to be promiscuous, thus insuring pregnancy. Mating can occur anywhere from January through July, usually at the peak of a rainy season when vegetation is abundant. During periods of drought only a few females will reproduce. Anywhere from one to six hairless blind infants are born in a fur-lined nest in the burrow. They learn to crawl quickly and develop their hind legs in their second or third week. Offspring can remain in the mound long after they are weaned; sometimes up to six or more months.

Folks driving in the desert at night are often startled by these animals appearing as small ghost-like creatures hopping across the pavement. Those of us who have spent nights in desert campgrounds know that kangaroo rats quickly learn to approach humans and accept tidbit handouts. They don’t appear to be disturbed by firelight or flashlights, providing opportunities to enjoy one of nature’s fascinating creatures.

Coast Silk Tassel Bush

Plant of the Month

Cliff Hutson
RSABG Volunteer, Nature Interpreter

 

Garrya elliptica (silk tassel bush)

A prominent American film director/actor was quoted as saying, “I do not wish to achieve immortality through my work. I wish to achieve immortality through not dying.” I suggest that another way would be to have a plant named after you.

Garrya elliptica, coast silk tassel bush, was named by the preeminent botanist David Douglas after his friend Nicholas Garry, of the Hudson Bay Company, who assisted him on his collecting expeditions. (Note: Over 80 species of plant and animal have douglasii in their scientific names, in Douglas’ honor.)

This shrub, a member of the family Garryaceae, grows in the chaparral, coastal sage scrub communities and foothill-pine woodlands below 3,000 feet. Look for it in the Garden along the path through the coastal and island communities at the eastern foot of Indian Hill Mesa.

Typically, its height is less than 8 feet, but it can be as tall as 15. Flowering occurs in late winter or early spring. The grayish green flowers appear as catkins and look as though they should be hanging from a graduation cap. Male catkins, which are longer, and female catkins are on separate plants; i.e., dioecious. The dried bracts, or inflorescences, hang on the bush well into summer much like light gray ornaments.

Ethnobotanic sources say that silk tassel bush was a remedy for stomach and intestinal cramping. Also, the wood was fashioned into a spatula-like tool that was used to pry abalone off of rocks and then separate the meat from the shell.

One of my field guides states that fruit hangs from the ends of the branches, as do the tassels. I have never observed this. I usually think of fruit as something sweet and fleshy (notwithstanding acorns, squash and so on) that can be eaten as food. But, botanists use the word fruit to mean any seed bearing structure formed from an ovary of a flower and shaped so as to aid in the seed’s dispersal. So, perhaps I should look more carefully.

Cricket, Cricket

Critters in the Garden

Carol Lerew
RSABG Volunteer, Nature Interpreter

Cool autumn days and evenings sometimes bring unexpected guests into the house. Hiding in carpeting next to a baseboard or tucked into a corner of a closet may be a cricket or two. It can introduce itself with loud chirping that stops, maddeningly, when you try to locate the fellow!

There are about 900 species of cricket, order Orthoptera, distributed throughout most parts of the world. They tend to be nocturnal and have a similar body structure to that of grasshoppers including jumping hind legs.

One of the most common is the field cricket, Gryllus pennsylvanicus. It is black to reddish brown, about an inch or less long, with black antennae longer than its body. Like all insects, it has three body parts: head, thorax, abdomen. Three pairs of legs are attached to the thorax. Two pairs of wings, held flat, cover the abdomen. The front wings are leathery and cover the hind wings. Females have a long ovipositor in the rear. Both sexes have segmented, tail-like appendages attached dorsally, called cerci. Tympanic membranes, located on the front legs, serve as sound receptors or ears.

The house cricket, Acheta domestica, is found mostly indoors. It can be about three-quarters of an inch long with the female somewhat larger. It is a yellowish brown with wings that project beyond the abdomen and cerci. Unfortunately, the house cricket, as well as the field cricket, can become a pest around human habitation—devouring seedlings, chewing on carpeting, eating food pantry items.

Crickets live under rocks, logs, in leaf litter in meadows, pastures, along roadsides, in damp places in our gardens and in buildings. Scavengers, they feed on organic materials such as decaying plants, fungi and some seedlings. Because crickets are cold-blooded they take on the temperature of their surroundings. Field crickets prefer to live outdoors but will move indoors when the weather grows chilly. In temperate climates field crickets usually die as frost arrives. The house cricket, much more adaptable, can live longer.

Field crickets mate in the late summer. Their eggs are deposited deep into the ground where they overwinter until spring. Nymphs grow by a series of molts, reaching adulthood in early summer. The house cricket continually lays eggs year-round depositing them in cracks, behind stoves, under floorboards.

Only the male emits the sound we identify as chirping to attract a mate, or to chase away rivals. It does this by running the top of one wing along the teeth at the bottom of the other wing. The wing membranes are held open to act as acoustical sails. It does not chirp by rubbing its legs together, as is commonly thought. As many of us can attest, the house cricket can be an indoor nuisance because of its continuous chirping.

Crickets are seen as good luck in many cultures and have been kept as pets in the Orient since ancient times. Tiny cages are constructed with great care, many of them exquisite in design, to house the tiny creatures. Crickets figure extensively in literature and some movies. Do you remember Jiminy Cricket in the Walt Disney movie, Pinocchio? He represented Pinocchio’s conscience. And, of course, many of us have read Charles Dickens’ The Cricket on the Hearth in which Dot Peerybingle rejoices that the cricket is “the luckiest thing in all the world.”

Laurel Sumac

Plant of the Month

Cliff Hutson
RSABG Volunteer, Nature Interpreter

One of my fondest memories as a teenager is running through the interior of Los Angeles’ Griffith Park right after a rain or on a cool foggy morning and smelling the fragrances of the plants of the chaparral and scrub-covered hills. One of the main contributors to that aroma was Laurel Sumac, then classified as Rhus laurina, but now known as Malosma laurina.

This 10 to 20 foot tall shrub is the only species in the genus Malosma. It is native only to Southern California and the Baja California Peninsula; and found in both the chaparral and coastal sage scrub communities between sea level and 3300 feet in elevation. The shiny red-green leaves are four to ten inches long and have a somewhat taco shell fold. When flattened, they have the shape of laurel leaves, which gives us the common name laurel, with sumac in recognition that it is in the sumac family—Anacardiaceae. (Just in passing, this family also includes cashews, mangos and poison oak!)

There is a specimen of laurel sumac at the Garden along the east side of the east mesa path between the restrooms and the entrance that leads to the Butterfly Pavilion area. It grows naturally in the hills fronting Thompson Creek in Claremont. This is fitting for its historic geographical and economic context for our region.

Malosma is not tolerant of hard frost, something it has in common with two important commercial crops in California. Anywhere it grows naturally turns out to be ideal for avocado and citrus as well. Growers became aware of this and began to use it as a sentinel plant when looking for land for their ranches.

While I began this essay by noting that I am fond of the fragrance, I would be hard pressed to describe it. I am not alone in this. The Jepson Manual says Malosma is Latin for “from odor which resembles that of an apple.” However, Nuttall's description says the aromatic odor is “something like that of the Bitter Almond." I suggest you check it out for yourself.

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.

California Fuchsia

Plant of the Month

Cliff Hutson
RSABG Volunteer, Nature Interpreter

It has been said that the only constant in the universe is change. The field of plant taxonomy is no exception. Thus, one nature interpreter has been heard to present this month’s plant as the “wildflower formerly known as Zauschneria,” as he tries to recall its new name.

Datura Wrightii

Plant of the Month

Cliff Hutson, RSABG Nature Interpreter


Datura is a member of the nightshade family (Solanaceae) and is common from central California to northern Mexico and east across the Southwest to Texas. Easily recognized by its white (sometimes tinged with violet), trumpet-shaped flowers on plants that grow 30 cm (12 in) to 1.5 m (5 ft) high and wide, it can be found in the Garden and, in some years, is seen along Thompson Creek in Claremont. However, two of my favorite field guides, "Introduction to California Chaparral" and "Introduction to the Plant Life of Southern California: Coast to Foothills," fail to mention it.

Coyote

Critters in the Garden

Carol Lerew
RSABG Volunteer

Dusk folds into night. An animal slips under the fence from the Bernard Field Station (read more about Bernard Field Station) and silently pads across the road toward Indian Hill Mesa. She trots steadily, ears perked, alert and wary. She is beginning an evening of hunting in Rancho Santa Ana Botanic Garden.