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A botanical mystery at Mission Trails

By Audrey F. Baker | Trail Guide

Among our most spectacular winter blooms is Mission Manzanita.

Its 0.3-inch flowers appear December to February, ranging from milk white to rose-pink and blending to yellowish tones at the open end. Prodigious urn-shaped flora assemble in small clusters near branch ends. When moist, these mini-mission bells broadcast opalescent hues. Bearing the strongest color of the flower, sepals often show bright red.

Spring transforms blooms into drupes (berry-like fruits) interplaying red against green, eventually aging into a glossy dark red to near black quarter-inch berries with little flesh, and large stone. Plants often retain last year’s fruit.

Mission Manzanita presents elliptically oblong, glossy, dark green leaves with a light felt-textured underside. As leaves age, their margins curl.

This slow-growing evergreen boasts multiple trunks. Ancient specimens can grow to 20 feet. The smooth, color-washed bark is tawnier than other manzanitas, showing little reddishness. Enwrapped branches project mystic imagery.

All manzanitas are in the Ericaceae (Heath) family and, with one exception, are members of the Artostaphylos genus. Mission Manzanita (Xylococcus bicolor) is that exclusion.

Dubbed the “fake manzanita,” it is the sole representative of the genus Xylococcus. The genus name comes from the Greek word for “wood berry,” and herein lies its main distinction. Its seeds are encased in a rock-hard stone. The species name, bicolor, references the leaves.

Its native range is limited and mostly confined to San Diego County with overlap into northern Baja with restricted strands in Orange, Riverside and Los Angeles counties, and Santa Catalina Island.

A Mission Manzanita in bloom with a white floral cluster (Photo by Audrey F. Baker)

Amid Mission Trails Regional Park’s southern mixed chaparral communities, Mission Manzanita resides principally on protected north-facing slopes and ridges, among other broad-leaved sclerophyllous plants (Laurel Sumac and Toyon), and on south-facing slopes where Chamise, speckled by Chaparral Candle (Yucca Whipplei), dominates our landscapes.

In both situations, the understory is fairly sparse.

Growing below 3,500 feet elevation, this sun worshipper requires sunny slopes with fast draining soil, and is aided by rocky conditions that reduce moisture loss and keep its roots shaded.

A great place to view Mission Manzanita is along Kwaay Paay Peak Trail.

You may spot a California thrasher probing its understory for insects, spiders and other invertebrates or competing with scrub jays to feed on berries.

Hummingbirds nectar from its flowers. Many animals use it for cover. Branches act as framework for a variety of nesting birds.

Most who pause to enjoy the Mission Manzanita’s beauty do not realize they are viewing an enigma. Its life cycle remains secret.

Historically, chaparral environs have not been vigorously studied. Even the question, “Has anyone ever found a Mission Manzanita seedling in the wild?” could not be answered.

Residents of chaparral require a strategy to combat fire’s devastation. Plants have three options — re-sprouting from a burl (underground roots), seeds cued into germination by fire’s effects, or the ability to employ both techniques.

While naturally occurring seedlings remain obscure and fire consumes most its seeds, Mission Manzanita is presumed to survive only through burl re-sprouting.

Rick Halsey, director of the California Chaparral Institute (Escondido) and frequent MTRP guest lecturer is among local scientists and layman delving into “Manzanitan mysteries.”

In 2004, he and colleagues began investigating the elusive seedlings, seeking to answer why a prodigiously seed-bearing plant does not appear to produce new wild plants.

When experiments at San Diego State could not resolve how these seeds germinate, Halsey sought to identify a missing element in the equation, a specific cue to signal germination.

Halsey’s hypothesis is based on a mutualistic relationship. A key resident of our coast and foothills, the now extinct California Grizzly Bear, bore a passion for berries. Scarification (the weakening/opening of the seed coat), through the process of Grizzly mastication or ingestion and expulsion, could serve to trigger germination.

May, 2008 provided a “Eureka!” moment in manzanita research. Scientists and volunteers converged on Balboa Park to conduct a “Bio-Blitz.”

The 24-hour marathon event to locate and identify as many plants and animals as possible turned up unexpected results. Jon Rebman, curator of botany at the Natural History Museum, discovered Mission Manzanita saplings in Florida Canyon!

Examinations at numerous sites in San Diego County beginning at Peñasquitos Canyon in January 2015 led to multiple seedling discoveries. While conditions of soil, sun and leaf litter varied, a unifying factor was a weather cycle of August and September rains, followed by wet December that maintained moist soil conditions.

Since these findings, no seedling found under mature plants have survived beyond a year. The mystery of the plant’s natural reproduction process remains. Existing plants continue to survive by their ability to re-sprout from basal burls. Like the beauty of its bloom, the enigmatic qualities of Mission Manzanita continue to intrigue.

—Audrey Baker is a trail guide at Mission Trails Regional Park. Reach her at aud1baker@gmail.com.

[Check the Mission Trails Regional Park Events Calendar published here or at mtrp.org. Call 619-668-3281 for more information on the park’s free offerings and opportunities to learn more about natural Southern California. Special walks can be arranged for any club, group, business or school by contacting Ranger Chris Axtmann at 619-668-2746 or at caxtmann@mtrp.org.]

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