Vaccinium ovatum Pursh: The Evergreen Huckleberry
Freya G. Holm
The Evergreen State College, Olympia, Washington 98505
Figure 1. Mature V. ovatum with light green new foliage. The Evergreen State College, May 2004.
Vaccinium ovatum, also known as the evergreen huckleberry, California huckleberry, or shot huckleberry, encompasses three distinct varieties: ovatum, saporosum (Leigh 1996) and scoparium (Szczawinski 1962). In the Ericaceae, the polyphyletic genus Vaccinium contains approximately 450 species of lianas and shrubs. It has been suggested that this morphologically diverse genus be divided into several clades to avoid redundancy with the tribe Vaccinieae (Powell and Kron 2002). Thirty-three sections have been recognized within Vaccinium (Sleumer 1941).
The range of V. ovatum spans the North Pacific coast, from British Columbia, Washington, and Oregon, south to California. The Kitsap and Olympic Peninsulas of western Washington host particularly abundant populations (Leigh 1996). Vaccinium ovatum occasionally occurs in the Cascade Range, as well as in the central Sierra Nevada and the Coast Ranges of the Pacific Northwest, inhabiting elevations from sea level to approximately 3,000ft (Tirmenstein 1990).
Coastal coniferous forests are commonly inhabited by V. ovatum. Preferred habitat is in low elevation forests, especially at edges and canopy openings. Dominant tree species associated with V. ovatum in mixed evergreen forests include Lithocarpus densiflora, Quercus chrysolepis, Pinus lambertiana, Pseudotsuga menziesii, and Arbutus menziesii. Humid coastal forests dominated by Chamaecyparis lawsoniana and Pseudotsuga menziesii, as well as communities of Sequoia sempervirens host V. ovatum as an understory shrub (Tirmenstein 1990). A truly coastal species, V. ovatum is often found on beaches in the salt spray zone (Pojar and Mackinnon 1994). Well-drained, humus-rich soils are preferred (Szczawinski 1962).
Figure 2. New branch of V. ovatum highlighting slightly pubescent stem and finely serrate leaves. The Evergreen State College, May 2004.
Vaccinium ovatum is an erect evergreen shrub that can grow up to 4m with slightly hairy young stems. Leaves are alternate, evergreen, finely serrate, and between 2-5cm in length (Hitchcock and Cronquist 1973). Developing leaves are generally light green. Mature leaves are deep, waxy green. With a slight fold along the midrib, leaves are dark green above and pale green beneath. Leaf color ranges from bright green to copper bronze when developing, to reddish-purple when in full sun (Leigh 1996).
Figure 3. New growth (foreground) of V. ovatum with mature growth behind. The Evergreen State College, May 2004.
Flowers are borne at axils in 3-10 flowered clusters. The corolla is gamopetalous, narrowly campanulate, and bright pink (Hitchcock and Cronquist 1973). Corolla length is up to 8mm with spreading triangular lobes. Calyx lobes are broadly triangular. Anthers feature long straight tubes above pollen sacs. Awns are generally not present on anthers, although they may be visible under magnification when present in undeveloped form (Szczawinski 1962).
Fruits of V. ovatum occur as purplish-black, sweet berries in profuse clusters. Globose and edible, the berries are 4-7mm thick with high acidity. There is considerable variation in flavor and quality of berries throughout the range of V. ovatum and among the three varieties (Szczawinski 1962). Fruits contain high concentrations of mono- and disaccharides, as well as ascorbic acid and calcium. Because V. ovatum produces fruits in clusters, it is able to produce 10 to 20 times more fruit than single-fruited huckleberries of similar size (e.g. V. parvifolium) (Tirmenstein 1990). Berries begin to ripen in early fall but often remain intact until December in some areas of the Pacific Northwest (Pojar and MacKinnon 1994).
Vaccinium ovatum is able to reproduce by seed or vegetative means. Certain birds and mammals widely disperse seeds. Uncommon among western huckleberries, V. ovatum reportedly does not possess rhizomes. Damage to aboveground foliage likely results in vegetative regeneration, which consists of sprouts growing from the well-developed root crown of V. ovatum (Westman and Whittaker 1975).
Vaccinium ovatum is utilized by a variety of organisms in the forest ecosystem. Deer and elk browse young stems and foliage. Chipmunks, black bears, grizzly bears, and humans eat berries. Many species of birds including thrushes, ptarmigans, towhees, ring-necked pheasant, and spruce, ruffed, blue, and sharp-tailed grouse also consume berries of Vaccinium spp. Columbian black-tailed deer were found to occasionally eat new leaves of V. ovatum (Cowan 1945). Both birds and mammals use V. ovatum thickets as hiding, resting, or nesting sites (Tirmenstein 1990). Flowers attract butterflies (Leigh 1996).
Vaccinium ovatum is also used by humans. Within the species range, the Nuu-chah-nulth, Sechelt, Comox, HalqÕemeylem, Straits Salish, Quinalt, and other groups historically used V. ovatum. Berries of many Vaccinium spp. were eaten fresh, commonly mixed with oil, or dried into cakes for wintertime nutrition (Pojar and MacKinnon 1994). Because of its attractive and long-lasting foliage, V. ovatum branches are commercially harvested and used by florists in floral arrangements (Szczawinski 1962).
Future studies of Vaccinium spp. could focus on phylogenetic relationships (Powell and Kron 2002), organisms responsible for seed dispersal and pollination, and fire ecology (Tirmenstein 1990).
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