Euphorbia lathyris L.
Mole plant, Petroleum plant, Caper spurge, Gopher plant
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
Sold, for example, by Maryland nurseries as the Mole Plant, this attractive
poisonous evergreen perennial belongs to a family, many species of which are
believed to repel moles. Castor bean is another Euphorbiaceous plant believed
to repel moles and other subterranean pests. Recently (Science 194:46. 1976)
Nobel Laureate Melvin Calvin has suggested that the mole plant could be the
"petroleum plant", producing a hydrocarbon substance very much like gasoline.
Calvin states that the hydrocarbon produced by the plant could probably be used
directly in existing refineries, after it had been separated from the water.
His estimates of 10 to 50 barrels of oil per acre per year seem optimistic as
do his cost estimates of $310 per barrel. If these estimates prove to be
correct, however, the petroleum plant would have virtues to outweigh its
poisonous and weed properties. Assuming 50 barrels of oil per acre per year at
a cost of $10 per barrel, a $15.00 sale price yields only $250 profit per acre.
If Calvin's optimistic estimates are proven, the plant merits further
attention. Guayule rubber has been estimated to give 6000 kg/ha latex
equivalent to only about 10 barrels oil per hectare (4 barrels per acre). It
is difficult to believe that Euphorbia lathyris would produce 10 times
more latex than guayule. However the latex in Maryland-grown material is
extremely copious. Calvin suggests that the plants could be simply cut down
and run through a crushing mill, new plants growing from the stumps. He
suggests that replanting would be necessary every 20 years or so. If he
produced 40 barrels an acre, he estimates it would take an area the size of
Arizona to meet our current gasoline requirements. Seeds are said to yield a
fine clear oil known as oil of Euphorbia, obtained by expression or by ether or
alcohol extraction. The latex is said to be depilatory. Uphof (1969) states
that the seeds are used as a coffee substitute. They are poisonous!
The oil has been used in soap manufacture.
French country folk are said to take 1215 seeds as a purgative, perhaps
similar in action and toxicity to castor oil. The root is equally purgative
and emetic. The leaves, like the latex, are vesicant, and have been used by
beggars to incite pity-producing blisters. According to Hartwell (19671971),
the latex is used in folk remedies for cancers and warts. Reported to be
antiseptic, cathartic, diuretic, emetic, POISON, and purgative, mole plant is a
folk remedy for cancer, corns, diarrhea, gangrene, melanoma, skin ailments,
sores, and sorethroats. Homeopathically the seeds are used for erysipelas,
paralysis, and rheumatism. The seed oil is applied to burns.
The L isomer of dopa [3-(3, 4-dihydroxyphenyl) alanine] is said to occur at
1.7% of the fresh weight of the latex. L-dopa is used for symptomatic relief
of Parkinson's disease, and is said to have produced some astounding
rejuvenating effects, inducing priapism, on some senile males who took it.
Leaves contain quercetin, quercetin-3-b-D-glucuronide, kaempferol,
kaempferol 3- glucuronide, b-sitosterol, p-coumaric acid, and ferulic acid.
Stalks contain hentriacontane, taraxerone, taraxerol, b-sitosterol, and
betulin. The energy-promising latex contains 0.5% 3,4-dioxyphenylalanine.
Sachs et al. (1981) got 6.2% rosin content (hydrocarbons) in nonirrigated,
compared to 4.4% on irrigated plots. The benzene extract of the leaves is said
to contain 0.1% (% of plant dry weight) rubber, and 0.2% wax; the acetone
extract 13.7% glycerides, 2.2% isoprenoids, and 8.3% other terpinoids. The
acetone extract of the seeds contains 40% glyceride. Per 100 g, the seed is
reported to contain 15 g protein and 4047.5 g fat. Seed contain
b-sitosterol, 7-hentriacontane, and daphnetin (List and Horhammer, 1969). I
predict that if all plants are studied in detail, they will be found to contain
both carcinogens and antitumor or cytotoxic compounds. This one contains the
antitumor compound b-sitosterol and the cocarcinogen ingenol-3- hexadecanic
acid ester (C36H58O6).
According to Hager's Handbuch, human overdoses result in burning mouth, nausea,
diarrhea, dilated pupils and collapse with pallor, rigidity, frigidity, cold
sweats, arrhythmic pulse, vertigo, delirium, alternating hot and cold flashes,
cramps, etc. (List and Horhammer, 19691979). The seeds are said to contain
aesuletin, and an unnamed alkaloid and the seed oil is violent POISON. The
plant has caused poisoning in children. Five California women are said to have
pickled the fruits, believing them to be capers. Severe but not fatal
Glabrous to glaucous succulent annual, biennial, perhaps perennial, to 1 m
tall, simple or branching if disturbed (coppices readily if top pinched), with
a copious white sticky latex. Leaves simple, entire, lanceolate, essentially
one-nerved, opposite or whorled on the stem, narrowly lanceolate, apically
acute, basally abruptly truncate, to 15 cm long. Leaves subtending flower
clusters broader, shorter, the flowers greenish yellow. Fruits usually
3-lobed, subglobose, 1/2 to 1 cm long. Seeds ovoid, flattened, 46 mm long,
Reported from the Mediterranean Center of Diversity, mole plant, or cvs
thereof, is reported to tolerate drought, frost, and poor soils. One might
detect two schools of thought on the feasibility of the petroleum plant, the
optimistic Calvin camp and the pessimistic Sachs school. Sachs et al. (1981)
say, "The implication that genetic improvement will greatly increase rosin
content is not well founded. We have no germplasm on hand for Euphorbia
lathyris to suggest that we can go much beyond 5 to 6 percent hexane
extractables... A recent world-wide search for new germplasm has not yet
uncovered E. lathyris plants with significantly higher rosin contents."
(2n = 20)
Native of the Mediterranean, cultivated as medicinal or ornamental, escaping
and self-seeding along the East and West coasts of the United States.
Introduced for example in Santa Cruz Co. Arizona, "to repel rodents in an
A hardy annual, biennial or perennial, self-seeding and overwintering in
Maryland, with great potential as a weed, ignored by grazing animals.
Ecologically the plant is estimated to range from Cool Temperate Dry to Wet
through Warm Temperate Dry to Moist Forest Life Zones, areas with annual
temperatures of 10 to 15°C, annual precipitation of 5 to 15 cm rainfall,
tolerating very sterile soils.
In California, Sachs et al sowed at a rate of nearly 250,000 seed per ha,
thinning to ca 80,000 or 150,000 or 190,000 plants per ha for their
experimental studies. Weekly irrigation replaced evapotranspiration, so that
there was little or no moisture deficit, except at the plot extremities. In
most tropical climates where chilling below 10°C does not exceed 1,000
hours, year-round plantings are satisfactory and planting dates can be chosen
to exploit rainfall or cropping rotation (Sachs et al., 1981). In greenhouse
tests, germination as high as 90% after 5 days at 23°C was reported.
At Davis, drying the petroleum plant is more difficult than drying oil seeds.
Plants harvested and left in early October were not dry enough for milling and
hexane extraction by early November.
White et al. (1971) reported seed (or fruit) yields of more than 3 MT/ha from
Beltsville (annual precipitation ca 10 dm, annual temperature ca 13°C). The
seeds contain nearly 50% oil, suggesting a potential seed oil yield of 1.5 MT.
In Sun Times (October, 1980) we read that Diamond Shamrock hopes to set 25
barrels of oil per acre from the latex. "Cost estimates for oil from
gopherweed range from $20 to $60 a barrel, compared to the current oil world
price of $32 a barrel." The bottom line, from an energy point of view, may rest
nearer. Sachs et al. (1981) who conclude that hydrocarbons from Euphorbia
lathyris would have to sell for $150 to $200 a barrel to be a practical
source of fuel. They got lower yields with propotionately higher biocrude
contents on their unirrigated plots. McLaughlin et al. (1982) report biomass
yields of 14 MT/ha/yr with 8% biocrude for a biocrude yield of 8.6 barrels per
hectare at a cost of $104/barrel ($31/GJ).
There is a bewildering array of reported yields for the petroleum plant, 22 MT
DM/ha (Nemethy et al., 1980), 19.824.7 barrels/ha/yr (mentioned by Sachs et
al., 1981), 16.319.3 MT DM/ha/yr (irrigated, Sachs et al., 1981), 10.314.7 MT
DM/ha/yr (fertilizer tests, Sachs, et al., 1981), 2025 barrels/ha/yr (Calvin,
1980). Calvin's early estimates of supplying gasoline sufficient to satisfy
U.S. requirements by planting an area the size of Arizona to Euphorbia
lathyris (40 barrels per acre). None of the estimates published in the 80's
approach that yield. Sachs et al. (1981) realized yields were closer to 5
barrels per hectare, suggesting it might take 20 Arizona's not one, to satisfy
U.S. petroleum needs, if planted to Euphorbia lathyris. According to
Nemethy et al. (1980), the heptane extract has a low oxygen content and a heat
value of 42 MJ/kg which is comparable to those of crude oil (44 MJ/kg).
Perhaps they are also optimistic in suggesting that the potential Euphorbia
lathyris yield is equal to that of sugar cane (11.7 x 104 MJ
ha/yr) adding the oil yield (6.5) and the alcohol yield (5.2 x 104
MJ ha/yr). Still, in the Sun Times (October 1980, p. 15) an anonymous source
says, "Melvin Calvin, Nobel laureate in chemistry, believes that the U.S. could
produce more than 2 million barrels a day of gopheroll by 1985. The Department
of Energy has granted Calvin $250,000 to continue his research. Marvin Bagby,
head of the Agriculture Department's hydrocarbon-plant research project, thinks
that gopherweed is the leader among forty-five hydrocarbon-bearing plants that
have commercial promise. McLaughlin et al (1982) project a biocrude yield of
41.8 GJ with a bagasse yield of 216.4 GJ/ha/yr. Assuming a 300,000 MT/yr
processing facility, the total energy requirements would be 1285 x
1012 J, the gross production of biocrude 895, the net electricity
production 1343 for a total net energy production of 953 x 1012 J at
a cost of $28/GJ or $104/bbl for the biocrude. The biocrude energy yield is
exceeded by the energy requirements, but the bagasse yield more than
Some diseases listed under this species are: Melamspora euphorbiae-dulces,
Phoma euphorbiphila, Pleospora herbarum, Sclerotium lathyris, Tithymalus
leiococeus, Aecidium tithymali, and Melampsora monticola. Sachs et al.
(1981) note in field plantings in California and Arizona, Pythium
aphanidermatum and Pythium ultimum were identified as
possible pathogens of Euphorbia lathyris, and pre- and post-emergence
damping-off caused by Pythium spp. was believed to be important in
limiting initial stands in some earlier California field trials. Greenhouse
experiments were conducted to determine whether seed treatment fungicides at
rates nontoxic to E. lathyris could satisfactorily control damping-off.
The fungicide diazoben (Lesan), widely used as a seed treatment to control
Oomycetes, was effective against P. aphanidermatum, P. ultimum, P.
carolinum, or P. vexans at rates as low as 0.1 gram active
ingredient per kg seed. Thus, all field plantings at Davis in 1980 were
diazoben-treated seed. Another disease, unrelated to Pythium
damping-off or root rot, occurred to some degree in each of the 1980 field
plots. Affected plants had stunted, yellowed foliage, and main and lateral
roots were blackened up into the crown and lower stem tissue. Microscopic
examination showed the blackening to be large numbers of small, black sclerotia
in the tissues. When affected tissues were cultured on potato dextrose agar,
they consistently gave rise to the sclerotial state of Macrophomina
pahseolina, which has also caused disease of E. lathyris in Arizona.
Macrophomina phaseolina is a serious pathogen of many crop species and
partially depends on high temperature and water stress in its invasion of plant
tissues. Indeed, in the Davis field plantings, disease symptoms appeared in
early- to mid-summer, and were most severe in plants under varying degrees of
water stress; well-irrigated plants showed no symptoms. The source of inoculum
in these plots is not known, but the severe levels of disease observed in one
plot suggest that the pathogen may have become established in the soil on some
other crop previously grown at the site. However, M. phaseolina also is
known to be seed-borne on many crops, and when diseased plants grown for seed
at San Jose, California, were examined, the pathogen was detected in host
tissues at least 50 cm above the soil line. Although the limited examination
of E. lathyris seed failed to detect the pathogen either on or in seed
or in seed debris, this question may warrant further investigation if E.
lathyris becomes widely cultivated. Nematode or the genus
Meloidogyne are reported.
Complete list of references for Duke, Handbook of Energy Crops
- Calvin, M. 1980. Hydrocarbons from plants: Analytical methods and observations.
- Hartwell, J.L. 19671971. Plants used against cancer. A survey. Lloydia 30-34.
- List, P.H. and Horhammer, L. 19691979. Hager's handbuch der pharmazeutischen
praxis. vols 26. Springer-Verlag, Berlin.
- McLaughlin, S.P., Kingsolver, B.E., and Hoffman, J.J. 1983. Biocrude production
in arid lands. Econ. Bot. 37: ca Spring 1983.
- Nemethy, E.K., Otvos, J.W., and Calvin, M. 1980. High energy liquid fuels from
plants. p. ???? In: Klass, D.L. and Emert, E.H. (eds.), Fuels from biomass.
- Sachs, R.M., Low, C.B., MacDonald, J.D., Awad, A.R., and Sully, M.J. 1981.
Euphorbia lathyris: a potential source of petroleum-like products. Cal.
- White, G.A., Willingham, B.C., Skrdla, W.H., Massey, J.H., Higgins, J.J.,
Calhoun, W., Davis, A.M., Dolan, D.D., and Earle, F.R. 1971. Agronomic
evaluation of prospective new crop species. Econ. Bot. 25(1):2343.
Last update Tuesday, January 6, 1998 by aw