A fence is covered with Merremia dissecta (Jacquin) Hallier f. near where a main street ends at the base of the Tucson Mountains in the southwestern part of the city. Within towns elsewhere in Arizona, the species appears occasionally in other yards (Austin 1998). For a long time I thought that the people were growing the twiners solely for ornament. The white flowers with red centers are attractive, as are the finely lobed and toothed leaves (Fig. 1). Since the 1990s, more information has been gathered; the story of cultivation is not always simple. Plants are cultivated in many parts of the world, but most books on horticulture and useful plants do not list this species. Merremia dissecta is, however, important to people for several other reasons as it has been since at least the 1800s. The purposes that people grow and move these plants are varied, because the vines are used in condiments, medicines, and as ornamentals. There is even one report of the roots being eaten in Argentina. This discussion brings together the scattered data on associations with humans to compare it with where the vines were introduced and the area of nativity of these American plants.

Fig. 1.

Merremia dissecta Left, original drawing by Jacquin (1767). Right, by author (Austin 1979).

Discovery and Distribution

Nicolaus Joseph von Jacquin discovered the vines now known as Merremia dissecta in the Caribbean between 1755 and 1759. He called the plants Convolvulus dissectus in his book Observationum Botanicarum published in 1767. The next year, Philip Miller (1768) named the same plants Convolvulus palmatus, either not knowing Jacquin's book, or not realizing they were the same species. It was only in 1773 that William Bartram found the species in northern Florida (Bartram 1943; Harper 1958). Both Jacquin (Fig. 1) and Bartram illustrated the species.

Jacquin did not record the island where he got the seeds that were subsequently planted in Vienna and that served as the basis of the illustration he published. He wrote “. . . nec occurrit certus collectionis locus” (“without occurring in any particular collection”). By contrast, Bartram found the plants in northern Florida in what now comprises Levy and Putnam Counties (Harper 1958). Miller's specimen came from Veracruz, Mexico (McDonald 1993). Not long afterward, the same species was found in Cuba (Ortega 1798), Georgia (Michaux 1803; Pursh 1814), and a number of other places in the Americas. These vines have now been spread around the world (Fig. 2), and have become naturalized in many places.

Fig. 2.

World distribution of M. dissecta. Closed circles = herbarium specimen seen. Open circles = literature reports. “A” = Adventive.

Weeds

There is disagreement about whether or not this species is native to the southern United States. Some consider it a native, although others think it alien (e.g., Wunderlin and Hansen 2003; Weakley 2006).

Certainly, by comparison with others, it was found in the region early enough to be considered native, having been discovered by Bartram in 1773 (Bartram 1943; Harper 1958) and in 1774 by Michaux (1803; Taylor and Norman 2002). Pursh (1814) knew M. dissecta from both Florida and Georgia.

Moreover, the species has a distribution that encompasses the entire circum-Caribbean region (Fig. 2) and it appears to be part of the native U.S. flora. Still, there had been ample time for Europeans and others to have moved the plants farther north by the time it was seen by Bartram and Michaux, and it is clear that people did move it elsewhere in the world. These plants are more common in coastal areas. Frequency along the coasts may be associated with the statements by both Michaux (1803) and Pursh (1814) that M. dissecta grew in calcareous soils.

Within Florida, the species is now spread throughout the state. Wunderlin and Hansen's (2004) map shows records from Escambia to Duval and south to Dade Counties.

Shinners (1970) did not mark this species as alien in Texas as he did others; he considered it native. Diggs et al. (1999) also thought the plants were native to Texas, at least as far north as Travis County.

By contrast, there are several places in the United States where the vine is not native. Merremia dissecta is adventive in Alabama, Arizona, Louisiana, Mississippi, and Pennsylvania. The Arizona report is based on plants growing outside a single subdivision in the Tucson Mountains (Rondeau et al. 1996), but she did not make a voucher of the plants (Jenkins pers. comm. 2006). The species is unknown in the wild elsewhere in the region (Austin 1998). The record for Pennsylvania is a single specimen taken from ballast ca. 1865 (Rhodes and Klein 1993). Similarly, single specimens are known from Alabama (Kral in 1971, MO), Louisiana (Thomas and Allen 1996), and Mississippi (in 1996, Lockley s.n. VSC). Plants in Georgia have been known since the late 1700s when they were found there by Michaux (1803), in Decatur, Glynn, and Wayne Counties (Jones and Coile 1988; Carter pers. comm. 2006). Nancy Coile (pers. comm. 2006) and Richard Carter, who know the living flora there, are undecided about its nativity. Occurrence of the species in five of these states is adventive. Although it may be native to southern Georgia, it is adventive farther north in that state.

These climbers are clearly alien in the Old World. By the 1900s or earlier the species was there and was included by some floras (e.g., Rendle 1905; Hutchinson and Dalziel 1931; Ooststroom 1939). Similarly, there is no doubt that M. dissecta is an exotic in Australia as has been noted numerous times (e.g., Barker et al. 2005; Groves et al. 2005). Humans have been moving this species around, probably both purposefully and accidentally, for many decades.

Maranhão and Irgang (2005) considered the plants alien in the state of Santa Catarina, Brazil, however they do not record which variety. Merremia dissecta var. edentata is native there (O'Donell 1941; Austin and Staples 1980; Austin and Cavalcante 1982; Bianchini pers. comm. 2006).

Ornamentals

Merremia dissecta is cultivated in the United States (Menninger 1964; Hortorium 1976; Rondeau et al. 1996; Austin 1998). Farther south in the Americas, the species is rarely grown, perhaps because plants are so abundant in wild places and in villages. In the Old World, however, they are widely cultivated.

Rendle (1905) recorded the species in Africa and considered M. dissecta “cosmopolitan.” Hutchinson and Dalziel (1931) were more exact and wrote that it was cultivated there and had escaped. In Asia, Hallier (1896), Ooststroom (1939), and Ooststroom and Hoogland (1953) noted the species in gardens of Malesia, particularly Java. Mansur (2001) also recorded the vines being cultivated in Southeast Asia. The plants do well in gardens in Australia, and are grown there in at least New South Wales, Northern Territory, Queensland, and Western Australia (Northern Territory Government 2006).

Seeds are offered for sale in the United States by many organizations (e.g., Isaacson 2000 and B & T World Seeds 2005). They are being sought for replacement in the New Orleans City Park since Hurricane Katrina (New Orleans City Park Improvement Association 2006).

There are several places in Germany where seeds are listed (e.g., Rare Plants 2006). Even in Australia, where M. dissecta is considered a terrible weed, seeds are for sale (e.g., Herbalistics 2006). Seeds are similarly sold in Taiwan (Plant Seeds 2006).

Flavoring and Medicines

Although flavoring and medicines may seem to be distinct, they are not to many people. Food, condiments, and medicines are not considered separate from each other in numerous cultures around the world (Etkin 2006). Several of the plant's common names refer to the smell or taste of almonds (Table 1). The almond taste (amygdalin and associated compounds) has a long history of involvement with humans, regardless of its source(s). Zohary and Hopf (2000) found that almonds (Prunus dulcis (Miller) D. A. Webb [= Amygdalus communis L.]) were domesticated in the Mediterranean not later than the third millennium BC. The many names for almond in southeastern European languages indicate a long history of human use in the region. These names include those based on Greek , such as Latin amygdalus, the Hebrew shaked and luz, Aramaic luz, as well as lauz [lõz] in Arabic, Kurdish, and other Semitic languages. Although neither the almond nor apricot (Prunus armeniaca L.) is native in the British Isles, the English were making a liqueur flavored with the kernels by 1785. The use of native British Prunus fruits and almond-flavored seeds for a variety of purposes is doubtlessly older in England as it was in Germany (cf. sloe gin in Fuchs 1542; Duke et al. 2002). Archaeological materials show that Prunus fruits were eaten in Europe by A.D. 1000 and perhaps as early as 200 B.C. (Priest-Dorman 1999).

Table 1.

Some common names for Merremia dissecta.

Table 1.

Continued.

Table 1.

Continued.

Noyau was in French by 1530 (Table 1), having been written noiel in the 13th century, in turn based on Latin nucalis, similar to a nut (nux), and came into English from French before the 1700s (OED Online 2003). By 1721 the phrase eau de noyau (almond liqueur) was in use in both languages (cf. Table 1 for more). Noyau in Caribbean French, but not in France, is a word clearly associated with almond odor and taste, although it specifically refers to kernel, pit, or stone. The seed within is amande for any species. Subsequently, noyau came to be associated with liquors flavored with almond or peach stones, e.g., Noyau de Poissy, one of the oldest liquors in France; established in 1698.

When the Europeans settled the New World they brought these ideas and practices to their new homeland. However, the indigenous people were inventive, imaginative, and inquisitive, and probably already had discovered the almond smell and flavor of M. dissecta on their own. Still, no records were found of any American use of this vine before Europeans arrived. Americans did use fruits and seeds of Prunus throughout its American range (cf. Austin 2004), so they were well acquainted with the almond smell and taste.

When and where M. dissecta began being used in the New World is unknown, but most records are from Caribbean and near-Caribbean people. Since the native range of M. dissecta var. dissecta includes that region, this pattern is not surprising. The year 1864, when Renato de Grosourdy published El médico botánico criollo, seems to be the earliest record of use by people in the Americas, although that publication surely was preceded by a long history.

Petersen (1974) wrote that in the Virgin Islands “Extract from the leaves of this vine, which smells almost like almond essence, is used as a flavoring in cake and sweet breads and candy. Noyau water also has a taste of prussic acid and is used in preparation of a liquor called Noyau.”

As medicine, Roig (1945) found that Cubans recommended crushed leaves as a sedative and for use in tisanes (infusions). Both forms were used for chest problems, applied against inflammation, and work as “resolutivas y sedativas a la par” (emollients and sedatives at the same time).

In Antigua and Barbuda, Grant (1995) noted that M. dissecta was used to treat colds. Hawthorne et al. (2004) infer by the common name “sprain-bush” that the plant was used to treat sprains in the Spice Islands of Grenada, Carriacou, and Petit Martinique. Morton (1981) learned from indigenous people in Curaçao that a hot infusion of “binibini” was given to relieve urinary infections. Veeris (1999) recorded similar uses. DeFilipps et al. (2006) wrote that a decoction of the plant was considered an effective external remedy for scabies and itch in the Guianas. García-Argáez et al. (1999) listed similar use in Mexico.

Outside the Americas, the species is also used. Dalziel (1937) recorded that in Nigeria a cold infusion was a remedy for giddiness and that in the Gold Coast it is given as a treatment for chest complaints in children. Ved et al. (2002) noted that the plants were used in “folk” medicine in three agro-climatic regions (Andhra, Telangana, Rayalseema) of Andhra Pradesh, India. Merremia dissecta is not, however, employed in Ayurveda or Unani systems, indicating a recent introduction to medicine as would be expected for a comparatively new plant. Mansur (2001) found that M. dissecta was employed to treat snakebite and intoxication in Africa.

Akana et al. (1922) called two plants kowali awa (harbor morning glory) and kowali pehu (swollen morning glory). They said that these have leaves “that resemble the palm of the hand,” white flowers, and that leaves of the latter kind are thicker and more round than the former. The two climbers were identified by H. F. Bergman, a professor of botany at the University of Hawai'i, as Ipomoea insularis (= I. indica (J. Burman) Merrill) and I. dissecta (= Merremia dissecta). No vouchers were made and the identity is spurious for the second species. This situation was corrected by Pukui and Elbert (1971) who listed I. alba for koali pehu. Pukui and Elbert were well versed in botany and their identification is probably correct, particularly since M. dissecta was not recorded in Hawaii until 1955 (Imada et al. 2005), and is not included among useful Hawaiian plants by Degener (1973) or Krauss (1974). Moerman (1998), using the misleading Akana et al. (1922), incorrectly thought that M. dissecta had been used as an analgesic, dermatological aid, laxative, orthopedic aid, pediatric aid, and strengthener in Hawai'i.

For Trinidad and Tobago, Williams and Williams (1969) simply indicate that M. dissecta is poisonous to cattle. Mansur (2001) found the same problem in India. Those problems must be caused by the prussic acid in foliage and seeds. Indeed, Nahrstedt et al. (1989, 1990) found that leaves and seeds contain several cyanogenic glycosides, including amygdalin, its 6″-(4-hydroxy) benzoate, and its 6″-(4-hydroxy)-E-cinnamate, prunasin, and 6′-O-malonylprunasin.

Alemán-Frias et al. (1972) did not detect them, but Jenett-Siems et al. (2005) identified 32 alkaloids in the roots, among them 6 pyrrolidines and 26 tropanes. Some minor metabolites they called merresectines were a novel type of tropane alkaloid characterized by prenylated benzoyl moieties as acyl components. Another novel congener, merredissine, was characterized as 3-α,6-β-di-(4-methoxybenzoyloxy)tropane. Moreover, calystegine B2, a polyhydroxynortropane, was detected in the flowers (Schimming et al. 2005).

García-Argáez et al. (1999) found other compounds. These authors discovered several caffeate esters in both M. dissecta and M. tuberosa (L.) Rendle. Merremia dissecta included a novel 6-methylheptadecanoyl caffeate, as well as lupeol, β-sitosterol, and stigmasterol.

Chemistry indicates that the early comparison with almond taste and notation that M. dissecta contains cyanogenic compounds were correct. Not surprisingly, Sena et al. (1997) found that extracts of the plants were antimicrobial.

Food

The only record found of the roots being eaten was recently published by Arenas (2003). Only M. dissecta var. edentata (Meisner) O'Donell is native in the Gran Chaco, Argentina, where Arenas worked with the Toba and Wichí people (Fig. 2), although there are scattered locations where M. dissecta var. dissecta has been introduced.

The second variety is restricted to South America and has not been dispersed outside that region (Fig. 2). Those plants were first discovered in Brazil, grown in the botanical garden in Bonn (horto botanico Bonoiensi), and called Ipomoea fulva by Giuseppe Bertolini in 1838. Then George Gardner found them in Rio de Janeiro and called them I. nigricans in 1842. Meisner, studying the family for Martius's Flora Brasiliensis, did not think that the climbers should be given specific rank and called them I. dissecta var. edentata in 1869. Meisner (1869) was obviously confused by this problem, because he also named them I. maximiliani in spite of their having two previous epithets at species rank. It was not until O'Donell (1941) examined the genus that the variety was moved to M. dissecta var. edentata.

While there are clear similarities between these two variations, corollas are completely white in M. dissecta var. edentata but white with a reddish-purplish center in M. dissecta var. dissecta. Moreover, the sepals average longer (20–35 mm.) in var. edentata than in var. dissecta (18–25 mm.). Leaf lobes in var. dissecta are toothed while those in var. edentata are mostly entire.

Arenas (2003) found only some of the Tobas using the plants, and although the Wichí formerly used them assiduously, only those in more remote villages still do. Roots are cut up if large, but left intact if small. The roots are put in a pot and boiled, or sometimes they are baked in ashes. Cooked roots are eaten with abundant oil as a dressing. Arenas thought that they tasted a little like the batata (Ipomoea batatas), although they tended to be insipid. Formerly they were taken entirely from wild places, but a few individuals now cultivate them in their home gardens. This is an important food only during the winter drought period.

Summary and Discussion

Merremia dissecta was discovered in the 1700s at nearly the same time in Florida, the Caribbean, and Mexico. Subsequently, the species was divided into two varieties, M. dissecta var. dissecta (Caribbean region) and M. dissecta var. edentata (South America, south of the Amazon River). Common names, ethnobotany, history, and distributions indicate that this species has been used by humans for multiple purposes. Variety dissecta was moved around the world by the 1800s, although the South American var. edentata has not been transported outside its native range. People moved var. dissecta because it is considered a condiment, medicine, and an ornamental climber. These various uses date from at least the 1800s. While the species has a venerable history of human association and use beyond being cultivated simply as an ornamental, it has not received wide acknowledgment for its various uses. Even in horticultural literature, the species has been slighted. Merremia dissecta deserves wider recognition and more study, particularly because of its association with an almond flavor, use to enhance food taste, and in medicines.