Monday, August 05, 2013

California's Native Cherry

Native plants are the basis for creating wildlife habitat. The scarlet blush spreading across the Catalina cherry fruit alerts birds, insects and even mammals that this important native chaparral fruit is ripening.

Frequently introduced fox squirrels will ravage the fruit before it can ripen, but as more of our native plants mature there is more fruit for all of our wild visitors to discover. Today the house finches, hooded orioles and mockingbirds are beginning to enjoy these plump cherries. And of course the plants themselves provide nesting locations for birds (Allen's hummingbird).

The native cherries of California’s chaparral are related to the bing cherries and other varieties that humans cultivate, but these are wild growing plants. The Catalina cherry (Prunis ilicifolia lyonii) is found across the southern California Channel Islands (Santa Cruz Island). It is closely related to the holly-leaved cherry (Prunis ilicifolia ilicifolia) found along coastal hillsides on the mainland. But as the name implies, holly-leaved cherry has a leaf with holly-shaped prickles. The chaparral plant evolved this protection to reduce browsing by deer and other large herbivorous animals.

We have both holly-leaved cherry and Catalina cherry growing in our yard. Their close ancestry means we also have hybrids of the two. The Catalina cherry has evolved over the last 10,000 years without a large herbivore. In the Channel Island ecosystem there was no need to protect its leaves from large browsing animals, so the plant stopped expending energy on prickly leaves. The edges of the leaves are smooth.

Instead the Catalina cherry put more resources into larger fruit to attract the Channel Island fox (Urocyon littoralis). The small omnivorous fox relies on fruit for much of its late-summer-to-autumn diet. It can swallow the large pit of the cherry and transport the seed to areas distant from the parent plant in its scat.

While the fruit of the Catalina cherry looks similar to a cherry you might eat, I had my own moment of discovery when I tasted one. This cherry has not been cultivated to western human tastes. It is edible. The skin is somewhat sweet, but the pale flesh is astringent. Only when it is almost over ripe does it lose its bitterness and become palatable. According to Jan Timbrook in her book, Chumash Ethnobotany, the fruit of the cherry or “islay” was more valuable to the native peoples than acorns.

The fruit was used two ways. On occasion the thin layer of very ripe flesh was eaten directly or was mashed and dried to create a kind of fruit leather. However the most valuable part of the fruit was the seed or pit. Typically the fruit was collected in large quantities and allowed to rot. The flesh was then removed and the pit was cracked open to reveal the seed kernel inside. Like acorns, these kernels were poisonous if eaten directly and they had to be specially treated. The kernels were washed a number of times, either in hot or cold water, to leach away a form of cyanide. Once the bitter-tasting poison was gone the kernels were boiled, made into a mash and formed into balls or cakes. According to Timbrook’s sources the cakes are bean-like in texture and taste. 

So valued were islay cakes that they were frequently placed as offerings at sacred locations.

I wonder how the Chumash discovered the process to take advantage of this resource? Why did they even think the seed was valuable? Did they observe bear, deer, rodents, birds or other animals that made use of this plant?

I have often seen the pits opened and the kernels eaten out by some animal, but I’m not sure who. Still more to be discovered in my own yard.  

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