Biological Sciences, Santa Barbara City College

Biology 100: Concepts of Biology


Toyon

Toyon on SBCC campus
Toyon is an evergreen shrub or tree growing to 6 – 15 feet in height with plant size and shape depends on its habitat. In exposed places Toyon is low and dense. In woodlands, it becomes more open, rangy and tree-like in shape. Toyon is common in the foothills and low mountains up to 4,000 feet. It is found in open woodlands and chaparral habitats and can be found with species of Quercus (oaks), Ceonothus, Arctostaphylos (manzanitas) and Salvia (sages). On the SBCC campus there are Toyon bushes behind the Humanities Building beside the fire road down to Pershing Park. Although widespread Toyon is not abundant. It is more common within the mesic (north slopes) chaparral and is often found in conjunction with scrub oak.


The dense foliage is composed of simple, evergreen leaves. These are elliptical, 2 – 4 inches long, with a serrated (finely toothed) margin. Leaves are dark green above with a lighter color undersurface.

Inconspicuous, bisexual white flowers appear in June and July. Fruits form and they slowly mature from green to red. By Thanksgiving and Christmas the distinctive, red, mature fruits can be found. Each bright red, berrylike fruit is approximately 0.25 inch in diameter and contains one or two, small brown seeds. Robins, mockingbirds and cedar waxwings are among some of the bird species who feast on the Toyon’s berries and assist with seed disbursal. Many Indian tribes also enjoyed these berries and would remove their bitter taste by roasting them over open coals or boiling them in a cooking basket.

Toyon berries and leaves
The pulp of immature fruits contains a toxic cyanogenic glucoside that protects developing fruits from bird predation. As the fruit ripens, the cyanogenic glucosides gradually shift out of the pulp and into the seed, pulp carbohydrate levels increase, and fruits turn from green to bright red. The fruits become more attractive to birds as they ripen, and bird dispersal of the seeds is encouraged. Subsequent seed predation is prevented by the localization of cyanogenic glycosides in the seeds.

After a fire, Toyon sprouts vigorously from dormant buds located on a root crown. The root crown also stores carbohydrates so Toyon is able to rapidly reoccupy the post-burn environment. These is very little seedling establishment immediately after a fire, and extended fire-free periods are required for seedling establishment to be successful and lead to expansion of Toyon populations. The young seedlings also require a period of higher than normal rainfall to create the moisture regime they need to survive. Seedlings on northern slopes with a well developed litter layer are more likely to be successful. Seedlings are also eaten to many browsing mammals so the long term survival of the seedlings is low.


Heteromeles arbutifolia. Hetero = different; meles = apples (fruits like little apples)
arbuti-folia = leaves
arbutifolia: having leaves like Arbutus unedo, the Spanish madrone


Kingdom Plantae – Plants
Subkingdom Tracheobionta – Vascular plants
Superdivision Spermatophyta – Seed plants
Division Magnoliophyta – Flowering plants
Class Magnoliopsida – Dicotyledons
Subclass Rosidae–
Order – Rosales
Family – Rosaceae - Rose family
Genus Heteromeles – Toyon

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