Common
Name:
Pawpaw, Custard
apple, Poor-Man’s banana, West Virginia (and several other states) banana – The etymology of Pawpaw is indeterminate
though it is postulated that the name is a linguistic variant of Papaya, a tree
native to the tropical regions of the Americas; both trees have lobed leaves
and oblong fruits. The name Papaya derives from either the Otomac papai or the Carib ababai. Pawpaw is also written as Paw-paw or Papaw.
Scientific
Name:
Asimina triloba
– The genus name is of French-Native American origin and probably derives from rassimina, the name given the Pawpaw by
the indigenous Illiniwek (also known as Illini) of the eponymous Illinois
region. Here rassi meant equally
divided longitudinally (bilateral symmetry) and mina meant with seeds – both referring to the fruit. The species
name is to describe the three (tri)
lobes (loba) of the flower.
The Pawpaw is a North
American original, the quintessential native plant. It is diminutive; an
understory tree that occupies the netherworld under the forest canopy, its
characteristic large, ovate leaves extended to gather the reduced light that
there prevails. What it lacks in stature, it compensates in the singular
quality of its namesake fruits; the custard apple is woodland ambrosia of
unexpected taste and texture. It is accordingly entwined with the historical
cultures of the wooded lowlands of the Native Americans and their colonial
successors.
Pawpaw’s
have the largest fruits of any indigenous North American plant. They were
widely used by Native Americans as edible and nutritious foodstuffs as
evidenced by observations of the earliest western encroachments into the
continent’s interior. Hernando De Soto, the noted peripatetic Spanish conquistador
who traversed a large swath of North America before succumbing to tropical
fevers on the banks of the Mississippi River in 1541, reported the widespread
cultivation of the trees by the native inhabitants. A narrative published in
Portuguese in 1557 by a member of the De Soto party says of the Pawpaw that “It
is a fruit … having a very good smell and an excellent taste. It is planted by
the natives through all the country.” Several centuries later, the Lewis and Clark
expedition found similar practices. As recorded by Captain William Clark on
September 15, 1806: “Passed the entrance of the Kansas River which was very low
….. We landed one time only to let the men gather Papawa (sic) or the Custard
apple of which this Country abounds, and the men are very fond of." Further interactions with Native Americans
revealed that the fruits were gathered and made into dried cakes
by the Algonquian, Siouan, Osage and Iroquois tribal groups and that the Cherokee
used the bark to make rope for stringing the fish they had caught – a practice
retained by the latter-day inhabitants of the Ohio River Valley. The Pawpaw
became a staple of the Appalachian Mountain people, as evident in the
children’s Pawpaw Patch Song:
Where, oh where is pretty little
Susie? Where, oh where is pretty little Susie? Where, oh where is pretty little
Susie? Way down yonder in the paw-paw patch.
Come on, boys, let’s go find her,
Come on, boys, let’s go find her, Come on, boys, let’s go find her, Way down
yonder in the paw-paw patch.
Pickin’ up paw-paws, puttin’ ‘em in
her pockets, Pickin’ up paw-paws, puttin’ ‘em in her pockets, Pickin’ up
paw-paws, puttin’ ‘em in her pockets, Way down yonder in the paw-paw patch.
It is hypothesized that
the Native Americans not only ate but also actively propagated the Pawpaw trees
to the extent that they became pervasive throughout the eastern half on North
America as was asserted by De Soto’s narrator. While the Pawpaw tree is very
good at vegetatively extending shoots from the expansion of extant rhizomes
(the ubiquity of the “Pawpaw Patch” in the song is a reflection of their
tendency to form patches due to vegetative growth), it is not at all very good at
establishing new colonies with the traditional seed dispersal and
germination method. The problem is one of poor pollination.
Although the Pawpaw forms a perfect flower in having both male and female
reproductive organs, it is not self – pollinating. The reason for this anomaly
is that it is protogynous, which means that the female stigma matures before
the male pollen is shed. A second factor
is that Pawpaw flowers have almost no scent, so that they are not very
attractive to pollinators. It has been
determined experimentally that the overall result of the Pawpaw’s lack of
fecundity is that only 0.41 percent of Pawpaw flowers on naturally pollinated
plants result in a fertilized fruit with seeds.
Recent efforts to establish commercial Pawpaw production have resulted
in a 17 percent fertility rate; this was achieved only by pollinating the
flowers by hand.
The poor reproductive capability
of the Pawpaw has inspired scientific speculation concerning the extent of its
geographic range that seeks to resolve the conundrum as to how it could have
spread throughout eastern North America on its own. The theory that it was a cultivar of Native
Americans is a possibility; however, a more intriguing hypothesis is that the
Pawpaw was spread by the now extinct megafauna of the Americas. A seminal paper
entitled “Neotropical Anachronisms: The Fruit that the Gomphotheres Ate” by
Janzen and Martin in 1982 posited that the existence of various plants having
fruits with large seeds was a vestige of the ecology of the Americas before the
invasion of Homo sapiens via
Beringia, the Bering Straits land bridge that joined the Eurasian and North
American land masses during the last Ice Age about 12,000 years ago (it is
widely believed that humans played at least a significant role in the demise of
American megafauna; the Gomphothere was
a large elephant-like quadruped) . The empirical underpinnings of the fruit-eating
megafaunal theory consist of three elements: (1) That large African mammals that
still exist eat fruits similar in taste and texture to the Pawpaw; (2) That the
current fruits attract a paucity of dispersers; and (3) That many of the
current fruits are not consumed by the large herbivores that now predominate
(e.g. deer and bears). The basic premise
is that the large seeds evolved in order to pass through the digestive tract of
a large animal where they would become activated by the chemistry of the
gastro-intestinal tract and deposited in nutrient-rich fecal matter for
germination. In addition to the Pawpaw, the Osage orange and the honey locust
also have an anachronistic aura; being in the wrong place at the wrong
time. A similar argument has been
proffered concerning the Dodo bird eating the seeds of the tambalacoque tree of
Mauritius; when the Dodo’s were decimated by human predation, the trees stopped
reproducing. However, scientific skepticism has prevailed and the extinct
megafaunal theory has for the most part been largely discounted as erroneous. The
fact remains that the Pawpaw is widespread throughout the eastern half of North
America and it is not likely that it was able to do that without a little help.
The popularity of the
Pawpaw among Native Americans and the Appalachian Mountain people was a matter
of taste. It is a matter of science that the Pawpaw is also nutritious. It has
a vitamin and mineral profile that is close to that of the banana. The average Pawpaw has about 80 kilocalories
with 1.2 grams of protein and 18.8 grams of carbohydrates and 1.2 grams of fat
(70 percent unsaturated). It is a particularly good source of vitamin C and
potassium (about the same as a banana), with higher levels of the necessary minerals
(calcium, phosphorous, magnesium, iron, zinc, copper and manganese) than
apples, oranges or bananas; in addition it has all of the essential amino
acids. It is worthy of note that a wild fruit growing in a natural organic
habitat produces an array of nutrients that is consistent with required animal
sustenance.
The medicinal potential
of Pawpaw has been a matter of interest to herbalists since the publication of Materia
Medica Americana by David Schoepf in 1787 who offered that “A wine prepared
from the unripe fruit is odorless and is highly useful in children’s sore
mouth.” Dr. A. Clapp subsequently reported
in Medicinal Plants
of the United States published in
1850 that the ground up seeds of the
Pawpaw were used by Native Americans and subsequently by colonists as an
insecticide, especially for the control of head lice. Since the fruits were
widely consumed by Indians, it is likely that the copious large, discarded
seeds were noted to repel insects which led ultimately to this etiology.
However, the authors of the 1898 King’s American Dispensatory report
that an experiment of the application of an aqueous preparation made from the
seeds and applied to the heads of children at the Children’s Home of Cincinnati
had no effect on the insects. The palliative properties of Pawpaw are also
addressed in 1854 by John King in The American Eclectic Dispensary
where he reported it to have emetic (vomit inducing) properties and that it was
used as a tonic by the local country people. A bitter alkaloid was eventually
isolated from Pawpaw extracts and named asiminine after the genus Asimina by Curtis and John Lloyd in the
1884 Drugs and Medicines of North America.
The advent of modern
medicine with its greatly expanded chemical assessment capabilities has sparked
a renewed interest in the medicinal and pesticidal properties of Pawpaw over
the past several decades. A group of
long chain fatty acids known as annonaceous acetogenins have been extracted
from various parts of the tree; three compounds named asimicin, bullatacin and
trilobacin show particular potency. As it turns out, the Native Americans were
right, Pawpaw is an effective and natural pesticide; a commercial product named
Pawpaw Cell-Reg is sold commercially for this purpose. Pawpaw may even have a role in the war on
cancer. Research with the annonaceous acetogenins has demonstrated that these
compounds act to limit the production of adenosine triphosphate (TSP), which is
the primary source of cell energy. The
tumor cells of cancer are problematic due to their rapid replication, which
takes a lot of energy. The inhibition of ATP restricts the ability of the tumor
to grow, as has been demonstrated in clinical trials.
Zebra
Swallowtail butterflies (Graphium
marcellus) lay their eggs exclusively on Pawpaw trees so that the hatched
larvae will eat the leaves, thereby imparting a measure of toxicity to the
adults to deter predation. The adult female butterflies have been observed to use
only young leaves for their eggs, presumably to impart the maximum benefit of
more concentrated chemical constituents. The larvae even have developed a more
direct means of protection. When disturbed by uninvited interlopers such as
spiders or ants, the larva extend a specialized organ called an osmeterium that
exudes offensive chemicals to drive them off. The alkaloids of the Pawpaw are
apparently as effective at convincing would –be predators that the Zebra
swallowtail butterfly is not palatable as is the milkweed plant for the Monarch
butterfly.