Apios americana Medik.
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Med and Vet Use
- Yields and Economics
- Biotic Factors
Attractively-flowered plant suggestive of Wisteria, described by the NAS
(1979) as a "useful, sweet-scented ornamental." I have enjoyed the tubers raw
or cooked. During the potato famine of 1845, Apios was introduced to
Europe. Its cultivation there as a food crop was abandoned when potato growing
again became feasible. The plant was much esteemed by Early American Settlers
who ate them boiled, fried, or roasted, calling them groundnuts, potato beans,
or Indian potatoes. The Pilgrims of New England survived their first few
winters by living on them. Krochmal and Krochmal (1974) give one recipe for
the root and one for the beans. Erichsen-Brown (1979) recounts many of the
Indian uses. Even bread was made from the root. Indians were said to eat the
seeds like lentils. I would like to join the ranks of Ed Croom, Janet
Seabrook, and Noel Vietmeyer and advocate more studies of the economic
potential of this interesting tuber, harvestable all year round. Advocates
should be aware of its weed potential, however.
According to Hartwell (19671971), the tubers were used in folk remedies
for that cancerous condition known as "Proud Flesh" in New England. Nuts were
boiled and made into a plaster, "For to eat out the proud flesh they (Indians)
take a kind of earth nut boyled and stamped" (Hussey, 1976).
Some describe the plant as having a milky juice. Seabrook (1973)
suggests that the latex could be used commercially. According to the NAS, the
only published analysis (Yanovsky and Kingsbury, 1938) records a remarkable
protein content of 17.5%. Duke, in an Appendix to the NAS book, mentions that
17.5 plus 57.1 g total carbohydrate and 4.7 g ash. Duke et al (1984) report
more than 17% crude protein, 5% ash, 3.5% fat, and 73% total carbohydrate on a
dry weight basis. At least 60% of the total N is protein. Tannin content
(10.35 mg/g) and trypsin inhibitor activity (2228 units/g) are twice that
reported for winged bean tubers. Saponins have been reported in the genus, and
the absence of tannins (Gibbs, 1974), refuted above. Whether or not the plant
exports its fixed nitrogen as ureides (allantoin, allantoic acid) as is typical
of many of the subtropical Phaseoleae or as the more soluble amides (asparagine
and glutamine) as in such temperate legumes as Lupinus, Pisum,
Trifolium, and Vicia remains to be seen. Because it is suggested to
have a cowpea type Rhizobium, I predict it will be a ureide exporter. Some
calculations suggest it takes ca 2 1/2 times as much water (remember this is an
aquaphyte) to export N as ureides. But the ureides are more economical with a
C:N ratio ca 1:1 cf 1:1 for asparagine, 5:2 for glutamine (Sprent, 1981). Many
legume sprouts are rich in allantoin, widely regarded as a vulnerary medicinal
compound. According to the Merck Index, allantoin is a product of purine
metabolism in animals, while it is prepared synthetically by the oxidation of
uric acid with alkaline potassium permanganate
Has been used topically in suppurating wounds, resistant ulcers, to
stimulate growth of healthy tissue (Merck, 1968). Dorland's Illustrated
Medical Dictionary puts it differently: allantoin (ah-lan'to-in) chemical name:
5-ureidohydantoin. A white crystallizable substance, C4H6N4O3, the diureide of
glyoxylic acid, found in allantoic fluid, fetal urine, and many plants, and as
a urinary excretion product of purine metabolism in most mammals but riot in
man or the higher apes. It is produced synthetically by the oxidation of uric
acid, and was once used to encourage epithelial formation in wounds and ulcers
and in osteomyelitis. It is the active substance in maggot treatment, being
secreted by the maggots as a product of purine metabolism. The direct role of
allantoin in gout, if any, should be of great intereat to the 8% of American
males who have gout, especially if they ingest large quantities of legume
sprouts or comfrey. Apios produces a complex pterocarpan that appears
structurally similar to glyceollin III, a phytoalexin of the cultivated soybean
Twining, herbaceous vine, the stems short-pubescent to glabrate, 13 a
long. the roots moniliform, with numerous, fleshy tubers 18 cm thick. In
winter the stems have a distinctive brown color and are locally flattened,
enabling the experienced collector to distinguish it from honeysuckle. Leaves
once-pinnate, 12 dm long; leaflets 57, ovate or ovate-lanceolate to
lanceolate, ca 36 cm long, glabrous to short-pubescent, obscurely stipellate;
petioles mostly 27 cm long; stipules setaceous, soon deciduous, 46 mm long.
Inflorescence 515 cm long, nodes swollen, flowers 12 per node, subtended by
linear-subulate bracts 22.5 mm long; pedicels 14 mm long with 2
linear-subulate bractlets near apex. Calyx sparsely short-pubescent, broadly
campanulate, tube ca 3 mm long; petals brownish purple, the standard obovate or
orbicular to obcordate, reflexed, obscurely auricled, 913 mm long, the wings
shorter, alightly auricled, the keel strongly incurved; stamens diadelphous, 1
and 1. Legume linear, 512 cm long, 47 mm broad, 2-many seeded, dehiscing by
2 spirally twisted valves (Radford et al. 1968). Germination cryptocotylar
Reported from the North American Center of Diversity, groundnut, or cvs
thereof, is reported to coterate acid and bog soils, slopes, and waterlogging.
In 1982, the Plant Introduction Officer of the USDA suggested to me the
possibility of mounting a germplasm expedition to collect germplasm of this
species, and its endangered relative, Apios priceana Robinson, which
produces a single large tuber instead of a string of small tubers. NAS (1979)
speculates that a bush-like mutant may be found in nature. Seedlings from
Tennessee had 22 chromosomes, while plants from the northern part of the range
were triploid. (2n = 22).
Widely distributed in eastern Canada and the US (often around ancient
Indian campsites) (Florida, Texas, to Nova Scotia. Minnesota, and Colorado).
Usually in low damp bottomland or riparian woods and thickets. Seems to be
associated with Alnus in Rocky Gorge Reservoir, Maryland, as well as on
the eastern shore of Maryland. Unfortunately, it can become a serious weed in
cranberry plots (Devlin, pers. commun., 1981). Perhaps the cranberry sales men
could find a market for the groundnuts, since both are Native American Food
Ranging from Subtropical Dry through Cool Temperate Forest Life Zones,
groundnut is reported to tolerate annual precipitation of 9.7 to 11.7 dm (mean
of 2 cases = 10.7), annual temperature of 9.9 to 20.3°C (mean of 2 cases =
15.1), and pH of 4.5 to 7.0 (mean of 2 cases = 5.8). Produces well in South
Florida. I have successfully germinated fall harvested seed, after soaking in
hot water, room temperature water, or frozen water, seeds that sunk and seeds
that floated after soaking. These took four months to germinate while their
unsoaked counterparts had still not germinated.
According to Vilmorin-Andrieux (1976), since seed do not ripen in
France, it is multiplied by division in March and April, or in the latter part
of summer. Divisions are planted in good, light, well-drained soil 11.5 m
apart in every direction. Stems should be supported by poles or stakes.
Ground should be kept free of weeds by an occasional hosing. Cultivation, if
overdone, might discourage the runner roots and their tubers. Seedlings
require at least two years growth and a minimum photoperiod of 14 hours to
induce flowering (Seabrook, 1973). Tuber dormancy can be broken by chilling or
According to Vilmorin-Andrieux (1976), the tubers are not large enough
to be gathered for use until the second or third year after planting. Once
large enough, they can be dug at any time of the year when the ground is not
frozen. If carefully dug, strings of four score tubers can be achieved.
According to Elliott (1976), Asa Gray once said that if advanced
civilization had started in North America instead of the Old World, the
groundnut would have been the first tuber to be developed and cultivated.
Fernald et al. (1958) recount an anecdote indicating the economic value of the
groundnuts to the pilgrims, "The great value to the colonists of this ready
food is further indicated by a reputed town law, which in 1654 ordered that, if
an Indian dug Groundnuts on English land, he was to be set in stocks, and for a
second offence, to be whipped." Duke et al (1984) report tuber yields from
cranberry bogs approaching 30 MT/ha.
Currently, this looks like a poor prospect for biomass production.
However, one should at least consider the possibility of developing the crop
for marginal habitat (swamp), the tubers as the main crop, the aerial biomass,
as residue, might be used for production of rubber, leaf protein, and power
alcohol. The nodulated roots fix nitrogen. Around Rocky Gorge Reservoir, in
Maryland, the plant is most commonly intertwined in N-fixing Alnus
species. Nodules were recorded on A. americana but root-nodule location
relative to tuber formation was not specified. Root hairs are said to be
lacking on secondary roots of mature plants. Four rhizobial strains isolated
from A. americana nodules were not tested on the host, but since they
produced nodules on cowpea plants, the species was considered a member of the
cowpea miscellany. The rhizobia are described as monotrichously flagellated
rods with cowpea-type, slow cultural growth (Allen and Allen, 1981). Duke et
al (1984) cite a personal communication suggesting conservatively, that the
Apios fixes >100 kg N/ha. With no idea of the solubility of N fixed by the
groundnut, I recommend it be studied as a potential intercrop for marsh and
aquatic plants, especially rice and wild rice. It might also be considered for
cultivation around the edges of reservoirs used for irrigation, hence adding a
small token of nitrogen to the irrigation waters. Because of their tolerance
to both acidity and waterlogging, they might be especially advantageous around
impoundments in stripmine reclamations. Certainly the scoring by Roth et al
(1982) do not speak well for the energy potential of Apios. They give
it a score of 14, in a system whereby only species receiving scores of 11 or
less were regarded as potential renewable energy sources.
Agriculture Handbook No. 165 lists the following diseases affecting this
species: Alternaria sp. (leaf spot), Cercospora tuberosa (leaf
spot), Erysiphe polygoni (powdery mildew), Microsphaera diffusa,
Phymatotrichum omnivorum, and Puccinia andropogonis var.
onobrychidis (rust). Although most Erythrinae are bird
pollinated, Apios seems to be mostly bee pollinated (Kalin Arroyo,
Complete list of references for Duke, Handbook of Energy Crops
- Allen, O.N. and Allen, E.K. 1981. The Leguminosae. The University of
Wisconsin Press. 812 p.
- Dorland's Illustrated Medical Dictionary. 25th ed. 1974. W.B. Saunders Co.,
- Duke, J.A., deLumen, B.O., Reyes, P.S., and Devlin, R.M. 1984. in ed. Chemical
composition of the american "groundnut" Apios americana Medik. J. Agr.
& Food Chem.
- Elliott, D.B. 1976. Rootsan underground botany and forager's guide. The
Chatham Press, Old Greenwich, CT.
- Erichsen-Brown, C. 1979. Use of plants for the past 500 years. Breezy Creeks
Press. Aurora, Canada.
- Fernald, M.L., Kinsey, A.C., and Rollins, R.C. 1958. Edible wild plants of
eastern North America. Rev. Ed. Harper & Bros., New York.
- Gibbs, R.D. 1974. Chemotaxonomy of flowering plants. 4 vols. McGill-Queens
University Press, London.
- Hartwell, J.L. 19671971. Plants used against cancer. A survey. Lloydia 3034.
- Hussey, J.S. 1976. Some useful plants of early New England. The Channings,
- Ingham, J.L. 1981. Phytoalexin induction and its taxonomic significance in the
Leguminosae (subfamily Papilionoideae). p. 599626. In: Pohill, R.M. and Raven,
P.H. (eds.), Advances in legume systematics.
- Kalin Arroyo, M.T. 1981. Breeding systems and pollination biology in
Leguminosae. p. 723769. In: Polhill, R.M. and Raven, P.H. (eds.), Advances in
- Krochmal, A. and Krochmal, C. 1974. A naturalist's guide to cooking with wild
plants. Quadrangle, New York.
- Merck & Co. 1968. The Merck Index. Eighth Edition. Merck, Rahway, NJ.
- N.A.S. 1979. Tropical legumes: resources for the future. National Academy of
Sciences, Washington, DC.
- Radford, A.E., Ahles, H.E., and Bell, C.R. 1968. Manual of the vascular flora
of the Carolinas. UNC Press, Chapel Hill.
- Roth, W.B., Cull, I.M., Buchanan, R.A., and Bagby, M.O. 1982. Whole plants as
renewable energy resources: checklist of 508 species analyzed for hydrocarbon,
oil, polyphenol, and protein. Transactions of Illinois Acad. Sci. vol. 75, 3
and 4, p. 217231.
- Seabrook, J.A.E. 1973. A biosystematic study of the genus Apios fabricus
(Leguminosae) with special reference to Apios americana medikus. Thesis.
Univ. New Brunswick.
- Sprent, J.I. 1981. Functional evolution in some papilinoid root nodules. p.
671676. In: Polhill, R.M. and Raven, P.H. (eds.), Advances in legume
- Vilmorin-Andrieux, Mm. 1885 (reprint 1976). The vegetable garden.
Illustrations, descriptions, and culture of the garden vegetables of cold and
temperate climates. The Jeavons-Leler Press, 885 Clara Drive, Palo Alto, CA.
- Yanovsky, E. and Kingsbury, R.M. 1938. J. Assoc. Off. Agr. Chem. 21:648665.
Last update December 29, 1997