Simmondsia chinensis (Link) Schneid. Family - Simmondsiaceae. Common Name(s) - Jojoba Synonym(s) - Buxus chinensis Link, Simmondsia californica Nutt.

Answer

Score

1.01

Is the species highly domesticated? (If answer is 'no' then go to question 2.01)

n

0

1.02

Has the species become naturalized where grown?

1.03

Does the species have weedy races?

2.01

Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical”

1

2.02

Quality of climate match data (0-low; 1-intermediate; 2-high) see appendix 2

2

2.03

Broad climate suitability (environmental versatility)

n

0

2.04

Native or naturalized in regions with tropical or subtropical climates

n

0

2.05

Does the species have a history of repeated introductions outside its natural range? y=-2

y

3.01

Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05

3.02

Garden/amenity/disturbance weed y = 1*multiplier (see Append 2)

n

0

3.03

Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2)

n

0

3.04

Environmental weed y = 2*multiplier (see Append 2)

n

0

3.05

Congeneric weed y = 1*multiplier (see Append 2)

n

0

4.01

Produces spines, thorns or burrs

n

0

4.02

Allelopathic

n

0

4.03

Parasitic

n

0

4.04

Unpalatable to grazing animals

n

-1

4.05

Toxic to animals

n

0

4.06

Host for recognized pests and pathogens

n

0

4.07

Causes allergies or is otherwise toxic to humans

n

0

4.08

Creates a fire hazard in natural ecosystems

n

0

4.09

Is a shade tolerant plant at some stage of its life cycle

n

0

4.10

Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island)

n

0

4.11

Climbing or smothering growth habit

n

0

4.12

Forms dense thickets

y

1

5.01

Aquatic

n

0

5.02

Grass

n

0

5.03

Nitrogen fixing woody plant

n

0

5.04

Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers)

n

0

6.01

Evidence of substantial reproductive failure in native habitat

n

0

6.02

Produces viable seed.

y

1

6.03

Hybridizes naturally

n

-1

6.04

Self-compatible or apomictic

n

-1

6.05

Requires specialist pollinators

n

0

6.06

Reproduction by vegetative fragmentation

6.07

Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1

>4

-1

7.01

Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)

n

-1

7.02

Propagules dispersed intentionally by people

y

1

7.03

Propagules likely to disperse as a produce contaminant

n

-1

7.04

Propagules adapted to wind dispersal

n

-1

7.05

Propagules water dispersed

7.06

Propagules bird dispersed

n

-1

7.07

Propagules dispersed by other animals (externally)

y

1

7.08

Propagules survive passage through the gut

8.01

Prolific seed production (>1000/m2)

n

-1

8.02

Evidence that a persistent propagule bank is formed (>1 yr)

y

1

8.03

Well controlled by herbicides

8.04

Tolerates, or benefits from, mutilation, cultivation, or fire

y

1

8.05

Effective natural enemies present locally (e.g. introduced biocontrol agents)

Total score:

-3

Notes

Reference

1.01

No evidence of selection for over 20 generations, although selection of varieties is currently in progress (1)Although other countries have grown jojoba for some time, their industry is based mainly on the use of ‘seeded’ material and yields are low and unreliable. Australia is well placed to become the world’s major producer of jojoba oil because of the varieties used, the amenable climate and the technical skills of our farmers.

(1)http://www.rirdc.gov.au/pub/handbook/jojoba.pdf [Accessed 08 Feb 2008]

1.02

1.03

2.01

(1)Perennial evergreen shrub endemic to the Sonoran desert (south west Arizona and California, Northern Mexico and Baja California)

(1)http://www.hort.purdue.edu/newcrop/cropfactsheets/jojoba.html [07 Feb 2008]

2.02

2.03

(1)Populations of jojoba are found in diverse climatic, geographic and edaphic conditions, at altitudes from sea level to about 1,200 m, usually on coarse, sandy or gravelly soils with good drainage. Native jojoba populations can be found in areas receiving an annual precipitation of 80-450 mm and having temperatures ranging from 9°C to 50°C (Gentry 1958). The plant is drought resistant and to some extent also salt-resistant. (2)Jojoba is mainly found in desert shrub habitats and lower elevations of chaparral vegetation [37,54]. In interior chaparral associations in Arizona, jojoba occurs with typical chaparral species on dry, open sites with an average shrub cover of 60 to 70 percent [40]. Although it is not listed as a dominant shrub species in available publications, jojoba is important over some parts of its range. Some minor associations in the Sonoran Desert are dominated by jojoba on rocky, upland sites within the paloverde (Cercidium spp.) type [30]. Jojoba is also dominant near Puerto Libertad in Sonora on piedmont and bajada sites [7]...Jojoba is climatically adapted to both mesic coastal climates and continental inland deserts [38].

(1)http://www.hort.purdue.edu/newcrop/cropfactsheets/jojoba.html [07 Feb 2008] (2)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [07 Feb 2008]

2.04

(1)Populations of jojoba are found in diverse climatic, geographic and edaphic conditions, at altitudes from sea level to about 1,200 m, usually on coarse, sandy or gravelly soils with good drainage. Native jojoba populations can be found in areas receiving an annual precipitation of 80-450 mm and having temperatures ranging from 9°C to 50°C (Gentry 1958). The plant is drought resistant and to some extent also salt-resistant. (2)In the United States, jojoba occurs in the Sonoran Desert from west Riverside and San Diego counties, California; east through Imperial County, California, to southern Yavapai and Greenlee counties, Arizona; south to Cochise, Pima, and Yuma counties, Arizona [18,23,35]. Jojoba is also distributed throughout Baja California and Sonora, Mexico, and is found on islands in the Gulf of California [4,5,17,23,35,38].

(1)http://www.hort.purdue.edu/newcrop/cropfactsheets/jojoba.html [07 Feb 2008] (2)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [07 Feb 2008]

2.05

(1)The product which is traded is called jojoba oil, potential world production of this product is currently around 3,500 metric tonnes per year, the major production areas being; USA, Mexico, Costa Rica, Australia, Brazil and Paraguay. Commercial plantations also exist in Argentina, Egypt, Israel and Peru. The total area covered by the crop throughout the world is currently around 8,500ha. In 1999-2001 Israel produced one third of the world production of jojoba, average yields are around 3.5 tonnes/ha (potential yield is 4.5 tonnes/ha), this is relatively high compared with production potential in Argentina and the USA.

(1)http://www.ienica.net/crops/Jojoba.pdf [08 Feb 2008]

3.01

Insufficient evidence of naturalization. (1)Introduced (Naturalised) Species to the United States [USDA, NRCS 1999. The PLANTS database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA. ] (naturalised)
List of Pteridophtyes and Spermatophytes for the Canary Islands (Lista de Pterido y Spermatoe Indice) Presence or Absence is denoted on an island by island basis and introduced (naturalised) taxa are also denoted. 2002. Viceconsejería de Medio Ambiente. Gobierno de Canarias. (naturalised) [not listed in Bramwell 1997. Flora of the Canary Islands.Editorial Rueda, Madrid]

(1)http://www.hear.org/gcw/species/simmondsia_chinensis/ [Accessed 07 Feb 2008]

3.02

No evidence, and unlikely considering poor competitive ability. (1)Jojoba grows slowly in the first few years and has little competitive ability against fast-growing annual weeds.

(1)http://www.rirdc.gov.au/pub/handbook/jojoba.pdf [Accessed 08 Feb 2008]

3.03

No evidence, and unlikely considering poor competitive ability. (1)Jojoba grows slowly in the first few years and has little competitive ability against fast-growing annual weeds.

3.04

No evidence, and unlikely considering poor competitive ability. (1)Jojoba grows slowly in the first few years and has little competitive ability against fast-growing annual weeds.

3.05

Monospecific (1)The Simmondsiaceae, the jojoba family, has only 1 genus, Simmondsia, which consists of only 1 species, jojobaCS. chinensis (Link) Schneider. Once considered an isolated member of the Box family (Buxaceae), jojoba is now regarded as sufficiently distinct to be placed in its own family.

(1)http://nsl.fs.fed.us/wpsm/Simmondsia.pdf [Accessed 07 Feb 2008]

4.01

(1)spineless

(1)http://cabezaprieta.org/plant_page.php?id=1133 [Accessed 07 Feb 2008]

4.02

(1)Known Allelopath: No

(1)http://plants.usda.gov/java/charProfile?symbol=SICH [07 Feb 2008]

4.03

Not parasitic

4.04

(1)Jojoba foliage is important forage for livestock and wildlife [9,15,18,32,46,54] and may provide the best browse available within its range [23]. Jojoba foliage is eaten by mule deer [4,25,31,54,55], desert bighorn sheep [33,49], jackrabbits [19], domestic sheep [4], goats [4], and cattle [4,15,32]. Cattle may browse jojoba severely enough to prevent any fruit development [15], and often consume it faster than it grows [4]. At the Kofa National Wildlife Refuge in Arizona, there were fewer crissal thrashers and brown towhees on grazed versus ungrazed areas due to the fact that heavy browsing had reduced the abundance and vigor of jojoba [48].

(1)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

4.05

(1)Toxicity None

(1)http://plants.usda.gov/java/charProfile?symbol=SICH [07 Feb 2008]

4.06

Not sufficient evidence of widespread, important economic pests. (1)It has been found that during the propagation of cuttings the dominant phytopathological problems in the nursery are caused by two species of Fusarium, F. solani and F. oxysporum. In addition, a number of other pathogens were observed: Alternaria spp., Pythium spp., Phytophthora sp., Rhizoctonia solani, Cylindrocladium sp., Diplodia sp., Colletotrichum sp., Phoma sp. and Erwinia spp. In jojoba plants in plantations, the major problems are infection by F. oxysporum and but also by F. solani. The symptoms of fusarium disease may include wilt and defoliation of leaves, which develop into desiccation and death of the plant. The infection may lie dormant and the disease can take hold in quite well-developed plants three and four years after the infection.

(1)http://www.hort.purdue.edu/newcrop/cropfactsheets/jojoba.html [07 Feb 2008]

4.07

(1)Toxicity None (2)Native Americans and early white settlers in the Southwest used jojoba nuts to make a substitute for coffee. Jojoba was also used by Native Americans for widespread medicinal purposes [4,12,23].

(1)http://plants.usda.gov/java/charProfile?symbol=SICH [07 Feb 2008] (2)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

4.08

Tolerant of fire, but apparently does not increase fire hazard. (1)Included on a list of some fire-resistant plants recommended for landscaping in high-risk fire areas (2)Easy to grow plants, distributed widely on hillsides around San Diego, and consistent with easy fire-zone management because their foliage resists ignition or they can be pruned easily to reduce fire risk.

(1)http://www.co.napa.ca.us/firewise/fw_about.html [Accessed 08 Feb 2008] (2)http://www.cnpssd.org/horticulture/ReplaceIcePlant.pdf [Accessed 08 Feb 2008]

4.09

(1)Shade Tolerance Intolerant

(1)http://plants.usda.gov/java/charProfile?symbol=SICH [07 Feb 2008]

4.10

(1)Populations of jojoba are found in diverse climatic, geographic and edaphic conditions, at altitudes from sea level to about 1,200 m, usually on coarse, sandy or gravelly soils with good drainage. (2)Jojoba is mostly limited to well-drained, coarse desert soils such as sandy alluviums and coarse mixtures of gravels and clays. These mixtures may be derived from igneous materials such as granite and other volcanics [4,15]. Soils are usually neutral to alkaline, high in phosphorous, and subject to annual drying [15]. Calcium carbonate content may also be high, especially in areas adjacent to mountain ranges with an appreciable content of limestone or calcareous sandstone [4]. (3)Soils with a pH of less than 5.0 are generally not suitable for jojoba because of aluminium toxicity problems.

(1)http://www.hort.purdue.edu/newcrop/cropfactsheets/jojoba.html [Accessed 07 Feb 2008] (2)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008] (3)http://www.rirdc.gov.au/pub/handbook/jojoba.pdf [Accessed 08 Feb 2008]

4.11

(1)Jojoba is a native, drought-resistant, evergreen shrub that may grow to 10 feet (3 m) or remain as a low mound 8 to 20 inches (20-50 cm) tall [4,15,18,35]. The form varies in different environments [15]; the more erect form is generally found on moist sites, whereas the semiprostrate form is found on desert sites [38]. Several stems arise from the root crown [15] and branching is profuse [15,18,23].

(1)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

4.12

(1)Jojoba reaches greatest dominance and forms pure stands on rocky slopes and valleys of the mountains north and east of Phoenix, Arizona, where annual rainfall is 15 to 18 inches (380-450 mm). Populations on good sites may have over 200 jojoba plants per acre [15].

(1)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

5.01

(1)Jojoba is a native, drought-resistant, evergreen shrub

(1)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

5.02

Simmondsiaceae

5.03

Simmondsiaceae

5.04

Not herbaceous

6.01

(1)Abstract: The reproductive success of an individual plant is in part a function of its capacity to assimilate resources, and this in turn is partially a result of plant morphology. Simmondsia chinensis, jojoba, a dioecious desert shrub, is dimorphic in secondary sexual characters in some desert populations, where females on average have larger leaves and more open canopies than males. The function of this sexual dimorphism was examined by investigating the importance of shoot morphology to reproductive components of plant fitness. The reproductive behavior of individuals tended to be associated with different morphological attributes for both males and females. Males with more "male-type" morphology tended to have more inflorescences and a greater likelihood of flowering than did males structured more like females, though they also had smaller inflorescences. Females with more "female-type" construction produced more flower buds in one of the study years and also produced heavier seeds than females with more male-like structure. Females from four different morphological classes allocated 1.5-4.5 times as much to reproduction as did males, but showed wide variability in whether or not they set fruit. Therefore females either had a much higher or a much smaller reproductive allocation than most males. Fruit set in the population studied is not limited by pollen availability, but is presumably constrained by abiotic resource availability. The asymmetry between sexes in the morphology of reproductively more successful individuals points to a potential for a resource-based evolutionary origin of sexual dimorphism in jojoba, arising from different morphological optima for each sex.

(1)Kohorn, L. U. 1994. Shoot morphology and reproduction in jojoba: Advantages of sexual dimorphism. Ecology 75(8): 2384-2394.

6.02

(1)Jojoba may be propagated by direct seeding at depths of 2-5 cm in wet, well-drained soil. A seeded plantation of jojoba has genetic heterogeneity, and low average yields.

(1)http://www.hort.purdue.edu/newcrop/cropfactsheets/jojoba.html [07 Feb 2008]

6.03

Monospecific (1)The Simmondsiaceae, the jojoba family, has only 1 genus, Simmondsia, which consists of only 1 species, jojobaCS. chinensis (Link) Schneider. Once considered an isolated member of the Box family (Buxaceae), jojoba is now regarded as sufficiently distinct to be placed in its own family.

(1)http://nsl.fs.fed.us/wpsm/Simmondsia.pdf [Accessed 07 Feb 2008]

6.04

(1)Jojoba is a dioecious wind-pollinated shrub, reaching a height of 1-5 meters and having a long life span (100-200 years). (2)Jojoba is wind pollinated [5,7,38]. Honey bees collect large amounts of pollen but apparently do not visit female plants [5]. Plants bearing perfect hermaphroditic flowers are rarely found in certain populations. Apomyxis does not occur. Pollination and fertilization must take place to produce fruits with viable seeds [5,38].

(1)http://www.hort.purdue.edu/newcrop/cropfactsheets/jojoba.html [Accessed 07 Feb 2008] (2)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

6.05

(1)Jojoba is a dioecious wind-pollinated shrub, reaching a height of 1-5 meters and having a long life span (100-200 years). (2)Jojoba is wind pollinated [5,7,38]. Honey bees collect large amounts of pollen but apparently do not visit female plants [5]. Plants bearing perfect hermaphroditic flowers are rarely found in certain populations. Apomyxis does not occur. Pollination and fertilization must take place to produce fruits with viable seeds [5,38].

(1)http://www.hort.purdue.edu/newcrop/cropfactsheets/jojoba.html [Accessed 07 Feb 2008] (2)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

6.06

Possibly, but insufficient evidence. (1)Jojoba sprouts from the root crown following damage to stems [8,15]. Thickets may develop as a result of shoot production from deep roots several feet away from the root crown [15]. Jojoba may also be propagated from softwood cuttings taken in late spring or early summer [15,38].

(1)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

6.07

(1)With good nutrition and weed control, plant height increased at a similar rate over the experiment at all but the most sandy site, where growth was consistently poorer despite similar climatic conditions and management. Stands established from seed had extremely variable yields. Some plants failed to produce seed after 8 years while other plants consistently produced fruit after year 4, with yields as high as 1 kg clean seed per bush by year 8. (2)Plants could start producing seeds in 5 years, but full production would not be attained for 8 to 10 years.

(1)Milthorpe PL and Dunstone RL.1989. The potential of jojoba (Simmondsia chinensis) in New South Wales. 1. Growth and yield. Australian Journal of Experimental Agriculture 29, 383–387. (2)http://www.hort.purdue.edu/newcrop/duke_energy/Simmondsia_chinensis.html [Accessed 11 Feb 2008]

7.01

Large-seeded and unlikely to be dispersed unintentionally (1)Jojoba fruits are dehiscent capsules that are generally one-seeded but may contain up to three acornlike seeds [5,15,18,23,38]. The seeds are light brown to black and are large, generally 0.6 to 1.2 inches (1.5-3.0 cm) long [5,15,38].

(1)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

7.02

(1)Jojoba is cultivated mainly in Arizona, Northern Mexico, Argentina and Israel. In Australia, Chile and India small scale planting is done. All new plantations are from vegetative propagated plants originating in cuttings from selected cloness. In Israel, about 700 ha were planted between 1990-1993.

(1)http://www.hort.purdue.edu/newcrop/cropfactsheets/jojoba.html [07 Feb 2008]

7.03

No evidence. Large-seeded and unlikely to become a produce contaminant. (1)Jojoba fruits are dehiscent capsules that are generally one-seeded but may contain up to three acornlike seeds [5,15,18,23,38]. The seeds are light brown to black and are large, generally 0.6 to 1.2 inches (1.5-3.0 cm) long [5,15,38].

(1)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

7.04

Relatively large-seeded. (1)Jojoba fruits are dehiscent capsules that are generally one-seeded but may contain up to three acornlike seeds [5,15,18,23,38]. The seeds are light brown to black and are large, generally 0.6 to 1.2 inches (1.5-3.0 cm) long [5,15,38].

(1)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

7.05

(1)Seeds are dispersed by animals and erosion [50]. [This is a plant of the Sonoran dessert, it is difficult to see how a water-dispresal strategy could evolve for this species]

(1)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

7.06

No evidence of dispersal by birds. (1)The fruit is a capsule containing one to three dark brown seeds that normally ranges in their dry weight between 0.5-1.1 g and contain 44-56% wax. Fruits ripens during the spring and early summer and seeds fall to the ground in late summer. (2)Most capsules split at maturity and release seeds, but they occasionally drop before opening and slowly disintegrate on the ground. A few capsules may remain on the plant for an extended period [38]. Seeds are dispersed by animals and erosion [50].

(1)http://www.hort.purdue.edu/newcrop/cropfactsheets/jojoba.html [Accessed 07 Feb 2008] (2)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

7.07

Some seeds dispersed by gophers storing them for food. (1)The fruit is a capsule containing one to three dark brown seeds that normally ranges in their dry weight between 0.5-1.1 g and contain 44-56% wax. Fruits ripens during the spring and early summer and seeds fall to the ground in late summer. (2)Most capsules split at maturity and release seeds, but they occasionally drop before opening and slowly disintegrate on the ground. A few capsules may remain on the plant for an extended period [38]. Seeds are dispersed by animals and erosion [50]...Pocket gophers carry away large numbers of seeds and deposit them in caves or burrows. Although most of the seeds are consumed, some seedlings have been observed from abandoned gopher burrows [7]. (3)The 1 to 3 large seeds are borne in a capsule that superficially resembles an acorn. This splits open apically and down the sides to release the seeds. As is the case with many large-seeded North American desert species, jojoba seeds are dispersed by scatter-hoarding rodents that are also their principal consumers (Castellanos and Molina 1990). Sherbrooke (1976) reported that only 1 heteromyid species in southern ArizonaCBailey=s pocket mouse (Peragnathus baileyi)Cwas able to utilize jojoba seeds. (3)The focus of the possible coevolutionary relationship between jojoba and P. baileyi considered above has been on the role of P. baileyi as a seed predator (see Janzen [I9711 and Smith [I9751 for reviews of seed predation by animals). It is also important to consider the role of P. baileyi as a seed dispersal
agent (see Janzen [I9691 and McKey [1975]). I have assumed that jojoba seed caches discovered in areas in the Tucson Mountains, where P. baileyi were the only rodents (except one Perotnyscus that refused a jojoba seed diet) trapped with jojoba seed bait, were stored by this species. Examination of hundreds of jojoba seedlings in the Tucson Mountains during the fall of 1974 confirmed previous observations that cached jojoba seeds germinate when there are sufficient rains. As many as 32 seedlings were found growing out of a single burrow complex. The germination of jojoba seeds requires a narrow range of warm temperatures (McCleery 1974), absence of light, and sufficient soil moisture (Burden 1970). The caching of seeds and disturbance of the soil by rodents may increase germination and seedling survival in some desert perennials (Greene and Murphy 1932, Greene and Reynard 1932, Reynolds and Glendening 1949, Reynolds 1950, 1958). Storage of large numbers of seeds, in excess of rodent needs, during years of abundance could benefit jojoba seedling establishment, even years later; seeds retain viability for several years (Gentry 1958).

(1)http://www.hort.purdue.edu/newcrop/cropfactsheets/jojoba.html [Accessed 07 Feb 2008] (2)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008] (3)http://nsl.fs.fed.us/wpsm/Simmondsia.pdf [Accessed 07 Feb 2008] (3)Sherbrooke, W. C. 1976. Differential Acceptance of Toxic Jojoba Seed (Simmondsia Chinensis) by Four Sonoran Desert Heteromyid Rodents. Ecology 57(3): 596-602.

7.08

Unknown if viable seeds survive passage through gut. (1)Jojoba is relatively abundant in the Tucson Mountains area and produces a an annual crop of nutritious fruits. Four percent of the total observed feeding time during July, August, and September was devoted to these fruits [Fruits consumed by collared peccary but no indication if viable seeds pass through gut] (2)Nuts are eaten by many animals, including squirrels and other rodents, rabbits and larger birds. However, only Bailey’s pocket mouse is known to be able to digest the wax. In large quantities, the seed meal is toxic to many mammals, and the indigestible wax acts as a laxative in humans. The Seri, who utilize nearly every edible plant in their territory, don’t regard the beans as real food and in the past ate it only in emergencies.

(1)Eddy, T.A. 1961. Foods and Feeding Patterns of the Collared Peccary in Southern Arizona. The Journal of Wildlife Management 25(3): 248-257. (2)http://www.desertmuseum.org/books/nhsd_simmondsiaceae.php [Accessed 11 Feb 2008]

8.01

(1)The period of flowering, the amount of fruit developed, and the quantity of seed produced is highly variable from year to year at any given location [7,15,38,50]. During 3 consecutive years at Puerto Libertad, Sonora, seed yield ranged from 0 to 448 seeds per plant [7]. (2)Early studies undertaken in the United States of America on wild stands or from small plots of seed-sown material generally reported low and highly variable yields (Gentry 1958; Thomson 1978; Hogan 1979; Yermanos 1982). Similarly, studies looking at the effect of irrigation also reported low and inconsistent yields from seed-sown plants (Ehrler et al. 1978; Forti and Heiman 1978)...The size and variation in yield of seeded jojoba grown at various sites in New South Wales is consistent with that reported in other countries and shows that. in a wild population, only a low percentage of plants consistently produce well. Apart from the 1986-87 yield at Trangie of 590 g seed plant- all other yields from seeded material at Rossmore, Trangie, Hillston and Condobolin have not exceeded 200 g seed plant-' in any year. In most years at least 80% of the yield came from lO-30% of female plants. In 1986-87 at Trangie, 46% of the female plants contributed 80% of this exceptional yield.

(1)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008] (2)Milthorpe PL, Dunstone RL .1989. The potential of jojoba (Simmondsia chinensis) in New South Wales. 1. Growth and yield. Australian Journal of Experimental Agriculture 29, 383–387.

8.02

(1)The seeds remain viable for along time [7,15,38]; almost 100 percent germination has been obtained from seed stored 10 to 12 years in sealed containers kept at 35 degrees Fahrenheit (1.5 deg C) [38]. The seeds may reside in the soil for many years before conditions are appropriate for germination [50]. (2)Jojoba seeds retain nearly 99% germinability after 6 months, and 38% after 11 years stored in an open shed.

(1)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008] (2)http://www.hort.purdue.edu/newcrop/duke_energy/Simmondsia_chinensis.html [Accessed 11 Feb 2008]

8.03

Unknown

8.04

(1)Jojoba was very tolerant of browsing near Roosevelt Lake in southern Arizona. It initiated new twigs from lateral buds to compensate for the loss of apical buds and twigs from herbivory. Heavily browsed plants maintained a ratio of photosynthetic biomass to total biomass as high as unbrowsed plants. However, heavy browsing greatly reduced shrub size and forage yield. Moderate browsing pressure resulted in forage yields similar to those of unbrowsed plants. Although browsing reduced shrub size, browsed plants maintained a water status similar to unbrowsed plants, even under high water stress. This indicated a comparable ability to balance transpirational water loss with water uptake through the roots. Jojoba was tolerant of heavy browsing, but moderate browsing was recommended to maintain greater shrub size and forage production [45,46]...Jojoba readily sprouts from the root crown and/or following fire in desert shrub and coastal sage scrub communities [8,15,44,58]. Fire may cause jojoba to take on a thicket or clonal form where shoots develop from deep sections of the main roots [15]. Seeds may survive fire in the seedbank if the fire is not too severe, but it is not known if they germinate well on bare mineral soil. Establishment may be limited after severe fire by lack of nurse plants.

(1)http://www.fs.fed.us/database/feis/plants/shrub/simchi/all.html [Accessed 07 Feb 2008]

8.05

Unknown.