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.
Potpourri: 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 green and eventually yellow fruit; 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.