California Blackberry

In Great Britain and/or Ireland:
Foodplant / parasite
effuse, hypophyllous colony of Peronospora rubi parasitises leaf of Rubus ursinus

More info for the terms: frequency, severity

Fire severity and intensity can influence the rate of postfire recovery
in California blackberry regardless of whether regeneration occurs
vegetatively or through seedling establishment. The following response
has been observed in western redcedar/queencup beadlily habitat types of
Idaho [52]:

mean frequency of occurrence
burn age in years

severity 1 2 3 4 5 15
low 33 82 71 74 98 0
high 71 80 68 74 100 0

California blackberry
California dewberry
California grapeleaf dewberry
Douglasberry
Pacific blackberry

More info for the term: cover

California blackberry provides important cover for a wide variety of
wildlife species [14]. Dense thickets of blackberries form good nesting
sites for many small birds including, thrashers, jays, pigeons, northern
mockingbird, sparrows, tanagers, and towhees [10,13]. The endangered
least Bell's vireo frequently nests in California blackberry thickets
along willow (Salix spp.)-cottonwood (Populus spp.)-oak (Quercus spp.)
ecotones in certain riparian areas of California [23]. Mammals such as
rabbits, red squirrel, black bear, and beaver utilize blackberry
thickets for cover in many areas [64].

More info for the terms: fruit, perfect, shrub

California blackberry is a low-growing, California or climbing, native
evergreen shrub [9,27,55]. This mound-building shrub can grow to 15 or
20 feet (5-6 m) in length [6,13,55]. The densely prickled stems are
greenish when young but turn brown at maturity [9]. The somewhat
prickly, deeply-lobed, alternate leaves are palmate and a lighter green
color beneath [9,13,27].

The stems of most blackberries are biennial. Sterile first-year stems,
known as primocanes, develop from buds at or below the ground surface
and produce only leaves. Lateral branches, or floricanes, develop in
the axils of the primocanes during the second year and bear both leaves
and flowers [24].

Perfect flowers of California blackberry develop in clusters of 2 to 15
near the ends of leafy branches [9,13,55]. Fruit is red and hard when
immature but shiny black when ripe [6]. Fruit is oblong or conical,
somewhat bristly, and up to 0.8 inches (2 cm) in length [9,55].
Aggregates of druplets, commonly referred to as "berries," are sweet and
flavorful at maturity [9,27].

California blackberry grows from British Columbia to northern California
and eastward to central Idaho [6,27,36]. It is particularly common from
the Cascades to the Pacific Coast [27]. California blackberry extends
through southern California into Mexico [9,55]. The subspecies
macropetalus occurs from British Columbia and Idaho southward into
northern California [36].

More info for the terms: duff, fire regime, forest, fruit, seed

California blackberry is a common invader on recently burned sites in the
Pacific Northwest [16,39,53]. Populations are capable of dramatic and
rapid expansion on disturbed sites [25,66] through sprouting or seedling
establishment [9,16]. Belowground regenerative structures are generally
well protected from the harmful effects of heat and permit rapid
recovery where California blackberry plants were present in the preburn
community. Seedbanking is also an important postfire regenerative
strategy [52]. Seeds accumulate in the soil or duff, remaining viable
long after this seral species has been eliminated from mature forest
communities. Seeds commonly germinate in great abundance after fire.
The relatively large, sweet, succulent fruit of blackberries amply
"reward" animal dispersers [40], and some postfire dispersal of seed
from off-site is probable.

FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find FIRE REGIMES".

More info for the terms: cover, forest

Timber harvest and slash burns: California blackberry commonly invades
logged and slash burned sites in the Douglas-fir zone of the Pacific
Northwest [39,61]. Reestablishment is rapid and can occur by the second
season after treatment [53]. In early postfire years, cover of California
blackberry is frequently as much as 3 times higher on slash burned sites
than in adjacent undisturbed stands [15]. California blackberry remains
prominent until suppressed by the closure of the forest canopy [25].
Schoonmaker and McKee [59] reported the following cover values after
clearcutting and broadcast burning in the Cascades of western Oregon:

yrs. since
tmt. 2 5 10 15 20 30 40 old growth

cover(%) 2.28 2.18 1.11 9.7 20.52 7.35 0.66 0.18

Stewart [61] observed similar increases after clearcutting and broadcast
burns in Coastal Oregon:

years preburn 1 3 4

cover (%) .20 .90 2.40 .20

Competition: California blackberry is favored by fire and can
aggressively compete with conifer seedlings in some postfire
communities.

Wildlife: Species which consume large amounts of blackberries are often
benefited by fire [45].

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More info for the term: hemicryptophyte

Hemicryptophyte

More info for the terms: fresh, shrubs

The California blackberry occurs across a wide range of sites from warm,
open areas to dense woodlands [27,36]. It is particularly common in
prairies, clearings, waste places, and canyons [36,55]. California
blackberry frequently assumes prominence on sites which have been burned
or logged [16,27,36] and on river terraces or gravel bars dominated by
red alder (Alnus rubra) [19].

Soils: Blackberries (Rubus spp.) grow well on a variety of barren,
infertile soils [6]. These shrubs tolerate a wide range of soil texture
and pH but require adequate soil moisture for good growth [10].
California blackberry appears to be tolerant of periodic flooding by
brackish or fresh water [65].

Elevation: California blackberry grows from sea level along the Pacific
Coast to middle elevations farther inland [27,36]. Generalized
elevational ranges for given locations are as follows [9,13]:

< 2,000 feet (610 m) in the Santa Monica Mtns., CA
< 3,000 feet (914 m) in southern California

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

210 Interior Douglas-fir
211 White fir
221 Red alder
222 Black cottonwood - willow
223 Sitka spruce
224 Western hemlock
225 Western hemlock - Sitka spruce
226 Coastal true fir - hemlock
227 Western redcedar - western hemlock
228 Western redcedar
229 Pacific Douglas-fir
230 Douglas-fir - western hemlock
232 Redwood
234 Douglas-fir - tanoak - Pacific madrone
246 California black oak
249 Canyon live oak

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

FRES20 Douglas-fir
FRES23 Fir - spruce
FRES24 Hemlock - Sitka spruce
FRES25 Larch
FRES27 Redwood
FRES28 Western hardwoods

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the term: forest

K001 Spruce - cedar - hemlock forest
K002 Cedar - hemlock - Douglas-fir forest
K003 Silver fir - Douglas-fir forest
K004 Fir - hemlock forest
K006 Redwood forest
K012 Douglas-fir forest
K014 Grand fir - Douglas-fir forest
K029 California mixed evergreen forest

More info for the terms: duff, seed, severity, shrub

California blackberry is described as "rather tolerant" of fire [25].
Although it may be top-killed [52], underground regenerative portions of
this shrub generally survive [9,52,61]. Fires of relatively high
severity or intensity, with the potential to harm belowground
regenerative structures, appear to be the most damaging to California
blackberry [52].

Most California blackberry seed stored on-site in the soil or duff is
probably unharmed by fire [52].

More info for the terms: cover, fruit, shrubs

Wildlife: California blackberry provides food and cover for many wildlife
species [9,14]. Blackberries are eaten by numerous birds, including the
ruffed grouse, northern bobwhite, sharp-tailed grouse, California quail,
ring-necked pheasant, blue grouse, gray (Hungarian) partridge,
band-tailed pigeon, American robin, yellow-breasted chat, pine grosbeak,
gray catbird, and summer tanager [3,10,64]. Jays, pigeons, northern
mockingbird, sparrows, tanagers, thrashers, and towhees, consume the
fruit of California blackberry and nest in its tangled branches [13].
Mammals, such as the coyote, common opossum, skunks, gray fox, red fox,
raccoon, squirrels, chipmunks, and black bear, consume the fruit of
blackberries [10,64].

Black-tailed deer feed on the stems and foliage of California blackberry
[13], and in some parts of California it is considered a preferred
browse [14]. In the Coast Range of western Oregon, leaves are selected
by deer in all seasons except summer, when a wide variety of other foods
are present [34]. In many areas California blackberry is particularly
important to deer during the fall and winter [12,35]. Deer often feed
heavily on the foliage until the leaves are covered by snow [12]. The
young leaves, which develop earlier than those of most other associated
shrubs, provide an important food source when forage supplies are lowest
and deer are threatened with malnutrition [34]. Hines and Land [35]
report that California blackberry browse is a preferred winter food of
black-tailed deer inhabiting Douglas-fir (Pseudotsuga menziesii) forests
of the Oregon Coast Ranges. In this area it supplied nearly 50 percent
of the total deer forage at the beginning of winter. In other winter
feeding trials, deer reduced the leaves and twigs of California blackberry
by as much as 80 to 89 percent [34].

Elk feed on California blackberry through much of the year in parts of
California, although utilization appears to be highest during the fall
and winter [30]. Rabbits, porcupines, mountain beaver, and beaver
occasionally consume the stems, leaves, and cambium of blackberries
[10,64].

Livestock: Blackberries, in general, provide only minimal browse for
domestic livestock. In some locations, California blackberry is
moderately grazed by domestic sheep but is rarely used by cattle [37].

More info for the terms: codominant, natural, shrub

California blackberry is well represented in a wide variety of plant
communities [9,54,55]. It has been identified as a codominant with
Columbia brome (Bromus vulgaris) and Shasta red fir (Abies magnifica
var. shastensis) in certain plant communities of the Cascades [8].
California blackberry is listed as a codominant in the following
publication:

Natural vegetation of Oregon and Washington [21]

Associated species: California blackberry grows as an understory species
with Shasta red fir, Pacific silver fir (A. amabilis), spruce (Picea
spp.), Douglas-fir (Pseudotsuga menziesii), white fir (A. concolor),
grand fir (A. grandis), western redcedar (Thuja plicata), western
hemlock (Tsuga heterophylla), bigleaf maple (Acer macrophyllum), and red
alder (Alnus rubra) [1,19,21,32,56]. California blackberry also occurs in
many West Coast riparian communities dominated by willows (Salix spp.)
or cottonwoods (Populus spp.) [23.42,62], as a codominant with
salmonberry (Rubus spectabilis) and thimbleberry (R. parviflorus), and
in baccharis (Baccharis spp.) shrub communities of the northern
California coast [31]. Common understory associates include Oregon
oxalis (Oxalis oregana), sweetscented bedstraw (Galium triflorum),
elderberry (Sambucus spp.), and other blackberries, raspberries, or
brambles (Rubus spp.) [21].

More info for the term: shrub

Shrub

More info for the terms: cover, shrub

Competition: California blackberry quickly assumes prominence on burned
or logged sites. After disturbance it can compete aggressively with
conifer seedlings in many locations. California blackberry frequently
makes up a large proportion of the shrub cover on scarified plots in
brushfields of coastal Oregon [43] and has been described as a principal
understory species in recently clearcut Douglas-fir forests of the
Olympic Mountains of Washington [19]. This highly competitive shrub
also becomes prominent on cutover sites in many coniferous forests of
both northeastern Oregon and northern Idaho [8].

Chemical control: Many chemicals including glyphosate, triclopyr, and
roundup, have proven effective in controlling California blackberry
[8,49]. Fifty to 80 percent control has been achieved with roundup in
some locations [49].

The specific food value of California blackberry browse has not been
documented, but it is considered to be good nutritionally [35]. In
feeding trials conducted by Hines [34], it was the only native browse
species capable of maintaining the weight of deer over winter. The food
value of California blackberry was found to vary seasonally, with the
crude fat content of the leaves peaking in the fall. Only slight
seasonal changes were noted in the crude fiber content of the leaves
[34].

AZ CA ID OR BC MEXICO

More info for the terms: fresh, fruit, vines

Fruits of the California blackberry are sweet and edible [27]. The
commercially grown loganberry, youngberry, and boysenberry were
originally derived from this species [54].

Native Americans historically ate fresh blackberries in summer. Fruit
was dried and combined with meat to make cakes which were eaten in
winter [13]. Unripened berries were soaked in water to make a cool
refreshing drink, and leaves or vines were used in making teas. Roots
were boiled in water to make various medicinal preparations [9]. The
fruit and stems of many blackberries have also been used to produce
various tonics or medicines [6].

More info for the term: shrub

Berries: Fruits of the California blackberry are sweet and succulent at
maturity [9]. Berries are palatable to many species of birds and
mammals.

Browse: California blackberry has been described as a relatively
unpalatable shrub [49]. However, in parts of California and presumably
elsewhere, deer exhibit a marked preference for the stem and foliage of
this plant. Most blackberries are relatively unpalatable to domestic
livestock.

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More info for the terms: fruit, phenology, seed

Seasonal development of the California blackberry varies according to
geographic and climatic factors. Phenology has been documented as
follows [6,9,13,27]:

location flowering fruit ripening seed dispersal

-- April-June June-August July-September
-- April-Aug. -- --
Santa Monica Mts.,CA Feb.-June -- --
s CA March-July -- --

California blackberry remains dormant during the winter [12].

More info for the terms: cover, density, fuel, herbaceous, seed, severity, shrub

Vegetative response: California blackberry is capable of vegetative
regeneration following fire through nonrhizomatous basal sprouts or root
"suckers" [9,52]. Basal sprouting is believed to be of primary
importance, and often results in a large number of sprouts [51]. This
low-growing shrub can also root at the stem nodes [37,65] and can
presumably spread quickly where portions of the aboveground stem remain
undamaged. Vegetative spread is generally both vigorous and rapid.
Stewart [61] observed an average of approximately 1,520 sprouts (plus
some surviving original stems) per acre (3,762/ha) within 2 year after
fire. Prior to the fire, an average of only 40 original California
blackberry stems had been counted within the same area. Evidence
suggests that all forms of sprouting may be favored after fires of
relatively low severity or intensity which are unlikely to damage
belowground regenerative structures [52]. Expansion of California
blackberry may be delayed on heavily burned sites [25,50]. Comparative
cover and density values of sprouts on a 2-year-old burn in western
redcedar/pachistima and western redcedar/queencup beadlily habitat types
in northern Idaho are as follows [50]:

low severity high severity

% cover 32.5 16.0
density 1.7 1.8


Seedling establishment: Seedbanking is reportedly an important means of
postfire reestablishment for the California blackberry [50].
High-severity fires, which burn to mineral soil, frequently create a
favorable seedbed for buried blackberry seed, and seedlings sometimes
germinate in abundance [52]. However in several instances, researchers
have observed decreased seedling establishment after unusually hot fires
with "much fuel consumption" [52,64]. Other factors, such as site
characteristics or climatic conditions, may have contributed to the
variable responses. Seedling establishment of California blackberry can
also occur through seed transported from off-site by birds and mammals.

Rate of postfire recovery: Sprouting produces the most rapid early
growth, as plants draw upon portions of previously established root
systems [52]. In many locations California blackberry has exhibited the
most rapid postfire expansion of any residual species [25]. This shrub
can dominate the herbaceous layer within 2 to 5 years after fire
[25,53,66]. Peak cover values have been reported from 0 to 5 years
after fire [25,51]. California blackberry is characterized by a
relatively long (> 5 years) period of postfire abundance and generally
persists until suppressed by canopy closure [25]. California blackberry
cover occasionally exhibits a temporary decline after rapid early growth
as one or a few stems attain dominance over many initial sprouts [50].
In western redcedar habitat types of northern Idaho, Morgan and
Neuenschwander [52] observed highest cover values in the third and fifth
years after fire, with California blackberry disappearing by the fifteenth
year. However, California blackberry frequently remains abundant for 11
to 16 years or more after fire in the Cascade Mountains of western
Oregon [59,60]. Halpern [25] reported that it remained prominent for at
least 20 years after fire in seral Douglas-fir forests of western
Oregon.

More info for the terms: geophyte, ground residual colonizer, rhizome, root crown, shrub

Tall shrub, adventitious-bud root crown
Rhizomatous shrub, rhizome in soil
Geophyte, growing points deep in soil
Ground residual colonizer (on-site, initial community)
Initial-offsite colonizer (off-site, initial community)

More info for the terms: apomixis, duff, fruit, seed, stratification

California blackberry exhibits vigorous vegetative regeneration but also
commonly reproduces through seed. Reproductive versatility is common in
the Rubus genus, with sexual reproduction, parthenogenesis (development
of the egg without fertilization), pseudogamy (a form of apomixis in
which pollination is required), and parthenocarpy (production of fruits
without fertilization) occurring widely. The following types of
reproduction have been documented in blackberries: (1) sexual
reproduction, (2) nonreduction at meiosis on the female, male, or both
sides, (3) apomixis (seed contains embryo of maternal rather than sexual
origin) with segregation, (4) apomixis without segregation, and (5)
haploid parthenogenesis [11]. These modes of asexual reproduction
contribute to the aggressive, vigorous spread of blackberries.

Vegetative regeneration: Most species within the Rubus genus are
capable of vigorous sprouting from root or stem suckers, or rooting stem
tips [24]. California blackberry sprouts readily from "suckers"
(presumably root suckers), or "nonrhizomatous sprouts" after fire or
mechanical disturbance [9,52,61]. It is also capable of spreading
rapidly from trailing stems which root at the nodes [37,65]. These
modes of vegetative spread occur even in the absence of disturbance.

Seed production: Most blackberries produce good seed crops nearly every
year [6]. During the first year of development, blackberries grow from
perennial rootstocks or creeping stems and produce sterile vegetative
shoots known as primocanes [24]. Lateral branches which produce both
leaves and flowers (floricanes) develop in the axils during the second
year [24]. Black shiny drupelets are produced on the floricanes of
California blackberry [6]. Fruit is oblong to conical, and up to 0.8
inches (2 cm) in length [55]. 384,000 per pound (845,814/kg) [6].

Germination: Blackberry seeds have a hard, impermeable coat and dormant
embryo; consequently, germination is often slow. Most blackberries
require, as a minimum, warm stratification at 86 to 68 degrees F (30 to
20 degrees C) for 90 days, followed by cold stratification at 36 to 41
degrees F (2 to 5 degrees C) for an additional 90 days [6]. These
conditions are frequently encountered naturally as seeds mature in
summer and remain in the soil throughout the cold winter months.
Laboratory tests indicate that exposure to sulfuric acid solutions or
sodium hyperchlorite prior to cold stratification can enhance
germination [3].

Seed dispersal: Fruit of the California blackberry is readily dispersed
by many small birds and mammals [27]. After they mature, the sweet,
succulent berries rarely remain on the plant for long [6].

Seedbanking: The seeds of most blackberries remain viable for at least
several years after being buried in the soil or duff [6]. Although the
precise length of viability has not been determined for the California
blackberry, Morgan and Neuenschwander [52] regard it as a species which
relies heavily on seedbanking for postfire regeneration. Average seed
densities of 290 per foot square (27 per m sq) have been reported in
western redcedar (Thuja plicata)/pachistima and western redcedar/
queencup beadlily (Clintonia uniflora) habitat types in coniferous
forests of northern Idaho [55].

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This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

1 Northern Pacific Border
2 Cascade Mountains
3 Southern Pacific Border
5 Columbia Plateau
8 Northern Rocky Mountains

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More info for the terms: climax, cover, eruption, forest, herbaceous, shrub

California blackberry is a vigorous competitor which commonly invades
disturbed sites created by logging, fire, or other types of disturbance
[16,39]. It is particularly well represented following "catastrophic
disturbance" in Douglas-fir forests of the Pacific Northwest [25], and
readily established on mudflows and other harsh microsites following the
eruption of Mount St. Helens. California blackberry typically increases
rapidly on disturbed sites, persisting until suppressed by canopy
closure [26]. It occurs in stands of all ages but reaches greatest
abundance in early seral communities [16,37,44]. Although primarily an
early seral species, California blackberry can sometimes persist in low
densities as a residual species in mature forest communities [16,59].
California blackberry was observed in initial postdisturbance, early
immature, late immature, mature, and old growth stands in coniferous
forests of southwestern British Columbia [44]. This shrub increases
rapidly and can dominate the herbaceous layer as early as 2 to 5 years
after disturbance [25]. In many western hemlock-western redcedar or
Douglas-fir forests of the Pacific Northwest, this shrub remains
dominant for at least 20 years after disturbance [2,25]. Bailey [2]
found that California blackberry increased to 50 percent cover 4 years
after disturbance, fluctuated between 25 and 50 percent cover for 20
years, and declined to 1 percent cover in climax stands. Maximum cover
values were reached 15 to 30 years after logging and fire in Douglas-fir
plantations in western hemlock-Douglas-fir habitats of western Oregon
[59].

California blackberry is present in red alder communities, which on
certain upland sites, appear to represent early seral stages of western
hemlock forests. Where these communities occur along streambanks,
periodic flooding can maintain species such as salmonberry and red alder
in long-lived, disclimax situations. California blackberry is considered
a major dominant in early successional stages of these communities [33].

Rubus macropetalus
Rubus ursinus var. macropetalus
Rubus vitifolius
Rubus ursinus var. medusae
Rubus ursinus var. sirbenus
Rubus ursinus var. ursinus
Rubus sirbenus
Rubus vitifolius ssp. ursinus

The scientific name of California blackberry is Rubus
ursinus Cham. and Schlecht. Recognized subspecies and varieties are as
follows [43]:

Rubus ursinus subsp. macropetalus (Dougl. ex Hook.) Taylor and MacBryde
Rubus ursinus subsp. ursinus

Many commercially grown cultivars have been derived from the
California blackberry [54].

More info for the term: seed

Blackberries, because of their ability to grow well on infertile soils,
may be valuable in preventing soil erosion on some sites [6,64].
California blackberry has been used to at least a limited extent in
rehabilitation projects in the West. Expected mortality was estimated
at approximately 50 percent following plantings in southern California.
Planting densities of 66 per acre (163/ha) were recommended for best
results [29]. Plants may be propagated vegetatively, transplanted, or
seeded onto disturbed sites. Seed which has been scarified can be
successfully planted in late summer or early fall [6]. Brinkman [6]
reports that cold treatment is not required for fall plantings.
Previously stratified and scarified seed can be planted in spring. Good
results have been obtained after seeds were planted with a drill and
covered with 1/8 to 3/16 inch (0.3-0.5 cm) of soil.

Rubus ursinus Cham. & Schlecht. Linnaea 2 : 11. 1827
Rubus Menziesii Hook. Fl. Bor. Am. 1: 179. 1832. Parmena Menziesii Greene, Leaflets 1 : 244, in part. 1906.
Stems biennial, climbing or trailing, finely and softly villous, sometimes almost tomentose, rarely glabrate the second year, armed with slender straight prickles; leaves of the turions ternate or unifoliolate; stipules subulate, small; petioles, petiolules, and midveins villoustomentose and armed with slender prickles; petioles 1-5 cm. long; leaflets of the ternate leaves broadly ovate, 3-6 cm. long, acute at the apex, obtuse or rounded at the base, green and short-hirsute above, paler and densely villous, at first almost white-tomentose beneath, coarsely double-serrate, with ovate teeth; blades of the unifoliolate leaves deltoid, 4-10 cm. long, cordate at the base, often 3-lobed, with the middle lobe larger; leaves of the floral branches ternate or the upper unifoliolate, similar to those of the young shoots, but with more rounded leaflets or lobes, often obtusish and broader above the middle, usually smaller; inflorescence corymbose, terminal and in the upper axils, as well as the hypanthium densely and finely villous-tomentose, usually copiously prickly, rarely very glandular; sepals tomentose on both sides, ovate, abruptly caudate-acuminate, 8-12 mm. long; petals of the staminate flowers oval or elliptic, 8-12 cm. long, white, those of the essentially pistillate flowers 6-8 mm. long, oval; fruit slightly elongate, about 10-12 mm. long, 8-10 mm. thick; drupelets numerous, tomentose; putamen faintly reticulate.
Type locality: San Francisco Bay, California. Distribution: California.

Rubus ursinus is a North American species of blackberry or dewberry, known by the common names California blackberry, California dewberry, Douglas berry, Pacific blackberry, Pacific dewberry and trailing blackberry.