Culinary herbs are herbaceous aromatic plants grown and marketed fresh or dried and include many of the same aromatic plants which are grown for their extractable essential oils. Significant quantities of dried culinary herbs are imported annually into the U.S. (Table 6). Recent estimates by the USDA Foreign Agricultural Service reported that more than $349 million of dried condiments, seasonings, and flavorings (Table 4) and $20 million of spice oleoresins were imported into the U.S. in 1988 (USDA 1989a). A significant amount of selected herbs are domestically produced for the dried spice or condiment market Domestic production of these and other herbs and spices now imported is increasing for both processing and fresh market.
The objectives of this paper are to provide an overview to the plants which are processed in the U.S. for essential oils and to identify fresh culinary herbs that are or can be grown in the continental U.S. The potential opportunities and constraints for production of these new crops in American agriculture will be highlighted.
The recovery of nonvolatile essential oils are also obtained by solvent extraction although the process is more difficult and complex than the recovery of the volatiles. This process yields an aromatic resinous product known as an oleoresin, which is more concentrated than an essential oil and which has wide application in the food industry (Heath 1981).
The recovery of citrus oils by mechanical expression is generally obtained by two types of commercial extractors, the FMC Citrus juice Extractor (FMC Corp.) and the Brown Extractor (Automatic Machinery Corp.) (Kealey and Kinsella 1979, Kesterson et al. 1971). Citrus oils are recovered as cold-pressed oils or as a specific constituent such a d-limonene as by-products of the juice and beverage industry and yield important aromatic and flavoring compounds used in a wide array of food, cosmetic and industrial products.
The other large quantity of essential oils produced as industrial by-products in this country comes from the wood and pulp manufacturing industries. More than 1650 tonnes of such oils, predominantly from cedarwood, are produced annually (Lawrence 1979).
The only other essential oil crop in the United States of significant volume is dill where the oils are used in the manufacture of pickles. Although dill oil can be obtained from the steam distillation of either seeds or foliage, it is often obtained by harvesting dill as a green herb after the seeds have formed but have not yet ripened. Dill seed oil is from the seeds and dill weed oil is from the green herb prior to flowering (Heath 1981).
While many other herbs have been produced for essential oil in limited quantities (Table 7), a complete list of crop species and production area is difficult to obtain and confirm. Most all the essential oils derived from temperate zone aromatic plants currently imported could be produced for essential oil domestically. However, opportunities for domestic production are limited because most essential oils from traditional herbs have limited markets making penetration into established markets very difficult. Many buyers and users have little interest in changing their suppliers unless supplies from abroad become limited due to political instability, contamination (such as the Chernobyl release of radioactive materials), or crop failure which permits new suppliers into the marketplace. An additional difficulty in establishing new sources of traditional essential oils is in demonstrating the ability to produce the quantity and quality demanded by the industry at a competitive price.
Many countries have government funded programs to establish new industries for export and which absorb much of the developmental costs associated with the evaluation and introduction of new crops. When these programs are coupled with crop champions and a strong relationship with the processing industry, the success of new crop development significantly increases. Such a program encouraged extensive work with several herbs for potential production in the prairies of western Canada (Embong et al. 1977a-e). Such programs have allowed Israel to go from an importer to a significant exporter of essential oils (128 tonnes of essential oils annually) in a relatively short time period (Putievsky 1989). International development programs have also contributed to the creation of essential oil industries. Technical assistance and funding from the Marshall Plan, enabled the large scale cultivation of herbs, spices and medicinal plants in Hungary (Mathe 1989). Prior to WWII, most Hungarian herbs were collected from the wild, but in part as a result of such an economic development program, Hungary has emerged as a significant exporter of cultivated essential oils (65,808 tonnes produced in 1982).
One of the challenges in developing new essential oil crops or in establishing a new geographical area for the production of an essential oil already on the market is procuring or developing generic lines with the suitable agronomic characteristics and desirable chemical constituents. The evaluation of a large and diverse germplasm collection thus becomes the first step in new crop development. This stage alone could take many years unless a processor supplies the particular chemotype that meets their processing needs. Unlike peppermint which must be vegetatively propagated, most essential oil crops are open pollinated and available seed have not been selected for homogeneity in growth or for flavor and aroma. Two examples will suffice to illustrate both the chemical diversity of herb cultivars and germplasm and approaches to crop improvement.
Parsley oil. Little information was available on the compounds responsible for the flavor of parsley and the genetic variability of the essential oil constituents of this important culinary herb. A recent study showed that essential oil content of a large germplasm collection ranged from 0.00 to 0.16% (v/fresh weight) and that the oil constituents varied significantly although the major constituent was 1,3,8-p-menthatriene, followed by ß-phellandrene, myristicin, and myrcene (Simon and Quinn 1988). In parallel study evaluating the essential oils of commercially available parsley curly-leaf types had as high essential oil content as the flat-leaf types, commonly believed to be more flavorful (Simon et al. 1989).
Basil oil. Sweet basil (Ocimum basilicum L.) is a popular culinary herb and a source of essential oils (ITC 1986) extracted by steam distillation from the leaves and flowering tops and used to flavor foods, in dental and oral products, and in fragrances. There are several types of basil oil on the world market European, French, or sweet basil; Egyptian; Reunion or Comoro; Bulgarian; and Java (Heath 1981). The European basil oils, considered to be the highest quality, contain methyl chavicol d-linalool and to a lesser extent 1,8-cineole, plus many other compounds (Guenther 1985, Simon et al. 1984). Egyptian basil oil is similar to the European, except that the concentration of d-linalool is lower and methyl chavicol is higher. Reunion or Comoro contains little d-linalool, but has a very high concentration of methyl chavicol (Lawrence et al. 1972, Simon et al. 1984). Bulgarian basil oil is rich in methyl-cinnamate and Java basil oil is rich in eugenol (Heath 1981). From an evaluation of the entire USDA collection plus other commercial and wild sources, we observed a wide range of chemical variation within O. basilicum and other species (O. canum, O. sanctum, O. gratissimum, and O. kilimandscharicum). We have identified chemotypes that represent each of the commercial types of basil oil. Promising lines are being screened for chemical stability, vigor, and uniformity. The characteristics of the population has continued to improve under mass selection. Isolation blocks serve as seed sources. We are currently developing a new line rich in methyl cinnamate (Simon et al. 1990).
Successful introduction of new plant sources of raw aroma chemicals for the fragrance industry could allow the rapid development of a new industry. An example is the development through selection of Monarda spp. rich in geraniol in Morden, Manitoba (Rafe Guadiel, personal communication) or Ocimum spp. rich in methyl cinnamate or methyl chavicol (Simon et al. 1990). The creation of new markets for specialized oils can take many years and would be most successful when working in collaboration with an end-user whose needs can be met by the new product.
The incorporation of new aromas into perfumes and fragrances and the development of new products is critical to the success of the perfumer and flavor chemist. The difficulty for the agricultural researcher is to learn the types of aromas and chemical constituents desired by the perfumer and flavorist. The identification of new species rich in desirable essential oils may be a promising route to pursue.
There has been tremendous growth in the fresh herb market as evidenced by the increased variety of herbs available both in the larger supermarkets, the smaller grocery outlets, farmers markets, and roadside farm markets (Simon 1986, Simon et al. 1989, Simon and Clavio 1989, Simon and Grant 1987a, b). Herbs that were only available dried, or fresh during a few months of the year, are now being marketed fresh cut and more recently, as live potted herbs in the produce sections of supermarkets all year long. Recognizing this growth, the USDA (1989c) now lists weekly prices for herbs sold in nineteen major wholesale markets plus the type of container, package, and weight count, and quality of each unit in the National Market News Report. The herbs now covered include anise, arrugala, basil, borage, chervil, chives, cilantro, dill ginger root horseradish, parsley lemongrass, marjoram, mint, oregano, rosemary savory, sage, sorrel tarragon, thyme, and watercress.
The successful introduction of new culinary herbs into commercial production requires a purposeful strategy and a solid information base. Unfortunately culinary herbs and essential oil crops have been studied little compared to all other food and fiber crops (Craker et al. 1986). While several extension guides have been published on herbs, few guides based on research are available in this country In a bibliographic review of the scientific literature from 1971-1980 (Simon et al. 1984), over 10,000 authors are listed with published research articles on the major economical herbs of the temperate zone involving horticultural research (38%), botany (17%), chemistry (14%), pharmacology (11%), ecology and germplasm (8%). With the exception of peppermint and spearmint most all crop research on herbs was conducted outside of the United States. Although the United States is the principal world producer of mint oils, only 10% of all published mint research from 1971-1980 originated in the U.S. (Craker et al. 1986).
Coriander (Coriandrum sativum L). This annual herb native to the eastern Mediterranean and southern European region has long been prized for its spicy aromatic seeds which are used either whole or in ground form as a main ingredient in curry and other food and flavor products. Coriander can be grown as a seed crop in the U.S. using existing mechanization and production technology but seeds ripen unevenly and the mature seeds shatter from the plant. Present demand for coriander seed is met by existing foreign suppliers and although the yield of coriander seed is moderately high (1,100-1,700 kg/ha) and the cost of production relatively low, there is still a question whether domestic commercial opportunities exist for coriander seed production as a spice. The profit margin of coriander would at best match the more traditional cash crops (maize, soybeans). Postharvest costs of cleaning the seed, handling and shipping can be major factors determining the profitability of this seed spice crop. Coriander seed is also processed via steam distillation for the extractable essential oil of which d-linalool is the major constituent. The oil is then used in the food and perfume industries.
Recently, American consumers have witnessed the introduction of coriander leaves into the marketplace. This fresh product, known as cilantro, is marketed in bunches as a leafy green spice. While new to American cuisine, cilantro has long been a popular herb in Oriental, Middle Eastern and Latin American cooking.
Coriander, a cool season crop, is easy to grow as a culinary herb and is most suited to fertile loam soils. The plant is direct seeded with a seed drill at rates of 13-18 kg/ha in very early spring. In Florida and New Jersey, coriander is often planted weekly At harvest, the whole plant is manually cut and bunched in the field.
One of the major problems in producing cilantro is premature flowering. Bolting becomes acute as the days get hotter and longer. A number of seed companies now offer slow-to-bolt (long-standing) cultivars. There are significant differences among coriander cultivars regarding the response to premature flowering, and while some are less susceptible, none are totally unresponsive to high temperatures and long days (Simon et al. 1989). Thus, cilantro is planted as a spring, early summer, or fall crop.
The aroma of cilantro is also due to an extractable essential oil, although its composition is distinctly different from the seed oil. Quality of fresh cilantro is based upon strong green color, strong aroma, and visual appearance (i.e. freedom from insects, discolorations). To the grower, yield and the cultivars' resistance to bolt are additional factors to be considered. Cilantro has a relatively short shelf life and requires refrigeration. Cilantro can be kept for 3 to 4 weeks at 0°C, but only 2 to 3 weeks when stored at 5°C (Cantwell 1989). Cilantro is routinely iced after harvest. Cilantro is expected to become increasingly important in the U.S. due in part to the expanding Hispanic and Arabic populations, its unique flavor, and increasing familiarity in the marketplace.
Sweet Fennel (Foeniculum vulgare Mill.). Sweet fennel has highly aromatic leaves and attractive green fern-like foliage but is best known for its seeds which are sold commercially as a spice. Limited domestic production for seed has occurred periodically, but demand is relatively small and adequate supplies can be obtained abroad. Successful domestic production of fennel for the seed as a spice will probably not occur unless the yields can be significantly improved, supplies from abroad become limited, or a government program makes the production of new crops more beneficial.
Fennel is a perennial but grown as an annual. It is most suited to well drained light loam soil. The plant is easy to grow and is typically direct seeded (3.5-5 kg/ha seed/acre) into the ground in beds with a specialized planter adapted to small-seeded crops. Plant spacing varies significantly with rows in the beds 60-1 00 cm apart and with final plant stands of 10-30 cm apart in the row. Fennel is a cool-season crop, seeds are sown in early spring and germinate at temperatures >7°C (optimum soil temp. approx. 16-18°C). Yields of up to 2,240 kg/ha have been achieved, although earlier USDA estimates were only in the range of 650-900 kg/ha (Sievers 1948). The plant requires 100-115 days to mature before harvest.
The production of fennel as a culinary herb, cultivated both for its aromatic leaves and enlarged leaf stalk is on the rise. This type, called Florence fennel or finocchio fennel, is a different subspecies than regular fennel produced as a seed spice. Very popular in Europe as a specially vegetable in many culinary dishes, it is commonly consumed raw in Italy and cooked in France. Finocchio is becoming commonplace in U.S. supermarkets and consumer interest and familiarity is increasing. One of the limiting factors to increased consumption is the public's unfamiliarity with it's preparation, use and taste. Unfortunately finocchio fennel is often marketed under the misnomer of anise, another culinary herb (Pimpinella anisum L.), which has led to market and consumer confusion. Both plants contain high amounts of anethole in the essential oil, imparting the licorice-like aroma and taste.
The time to harvest fennel bulbs is difficult to assess because the thickened leaf stalk continues to grow and develop until flowering takes place. Care in harvesting, grading and packing fennel must be taken to ensure a high quality fresh pack. Harvesting, cleaning, trimming and packing is done by hand. The foliage must be dark green and fresh in appearance and the stalk and bulb (enlarged base of leaf stalk) a lighter greenish-white color. The bulb must be firm and the product free from insects and discolorations. Once harvested, fennel should be kept at 0 to 2°C (Seelig 1974). The plants are retailed individually, either wrapped in plastic or simply displayed like celery.
Great variability (in growth and aroma) in commercially available cultivars of fennel and finocchio fennel exist (Simon et al. 1989) making the proper selection of cultivars for spring and fall production important. Finocchio fennel shows excellent potential for future growth in the U.S.
Oregano (Origanum spp.). Their has been a significant increase in the consumption of oregano for both the fresh and processed market (Tucker 1987). Oregano, the common name for a wide number of plant species with a characteristic aroma and flavor, is a perennial aromatic plant native to the dry calcareous soils of southern Europe, southwest Asia, and the eastern Mediterranean (Simon et al. 1984). A major problem which has limited domestic production was in the difficulty in distinguishing the many plant species and types of oregano imported and marketed as oregano. Imported oregano was found to be derived from 16 plant genera and more than 40 plant species (Calpouzos 1954), resulting in oregano being described as a flavor and aroma rather than an individual plant. Taxonomic work by Tucker (1986, 1989) has identified the major types of commercial cultivars and cultivated taxa in this country and the major types of imported oregano. Yet much of the imported oregano arrives as a blend of plants. Selection of an individual line for domestic production, particularly for the dried leaf or as an essential oil, remains difficult.
The European type of oregano comes mainly from subspecies of O. vulgare L. including ssp. hirtum (Link) Ietswaart, ssp. virens (Hoffmanns. & Link) Ietswaart and ssp. viride (Boiss.) Hayek (Tucker 1989). In contrast Mexican oregano, also called Mexican sage, is principally gathered from the small Mexican shrub, Lippia graveolens H.B.K. (Simon et al. 1984), although leaves from other species are collected.
The essential oil of European oregano is composed mainly of carvacrol and thymol. The range of each can be very wide and many chemotypes are available. The herb or the extracted oil is used in a variety of meat and sausage products, salads, stews, sauces and soups. European oregano and to a larger extent Mexican oregano, are used in flavoring Mexican foods, pizza, and barbecue sauces.
Oregano is generally transplanted to the field and grown on light, dry well-drained soils for periods of 3 to 6 years. Domestic horticultural studies on this species are limited. Although yields of more than 14 tonnes fresh herb/ha or almost 4 tonnes dried herb/ha were obtained from one commercial line by a single annual harvest (Simon et al. 1989), typically yields are much lower (1.5-3 tonnes dried herb/ha). Plants can be harvested multiple times each year (from 2 to 6) depending upon the location and end-use. Opportunities exist for dried product as well as for the fresh market. Once harvested for the fresh market oregano should be kept at 0deg.C to maximize shelf-life (Cantwell 1989).
|Cedar leaf oil||Thuja occidentalis L. (American or eastern white cedar|
|Balsam fir oil||Abies balsamea (L.) Mill. (Balsam fir)|
|Hemlock oil||Tsuga canadensis (L.) Carr. (Canadian or eastern hemlock)|
|T. caroliniana Engelm. (Carolina hemlock)|
|T. heterophylla (Raf) Sarg. (Western hemlock)|
|T. mertensiana (Bong.) Carr. (Mountain hemlock)|
|Spruce oil||Picea glauca (Moench) Voss (White spruce)|
|P. mariana (Mill.) BSP. (Black spruce)|
|Tsuga canadensis (L.) Carr. (Canadian or eastern hemlock)|
|Cedarwood oil||Juniperus mexicana Scheide (Texas cedarwood)|
|J. virginiana L. (Virginia cedarwood or red cedar)|
|Sweetbirch oil||Betula lenta L. (Cherry birch, sweet birch)|
|Wintergreen oil||Gaultheria procumbens L. (Wintergreen)|
|Grapefruit||Citrus x paradisi Macfady|
|Lemon||Citrus limon (L.) Burm. f.|
|Lime||Citrus aurantifolia (Christm.) Swingle.|
|Orange, Sweet||Citrus sinensis (L.) Osbeck|
|Tangerine and Mandarin||Citrus reticulata Blanco|
|Peppermint||Mentha x piperita L.|
|Spearmint (native)||M. spicata L.|
|(Scotch)||M. x gracilis Sole|
|Other spice oils|
|Nutmeg||Myristica fragrans Houtty|
|Pepper||Piper nigrum L.y|
|Pimento (Allspice)||Pimenta dioica (L.) Merrilly|
|State||Area harvested (1,000 ha)||Avg. yield (kg/ha)||Value ($1,000,000)||Area harvested (1,000 ha)||Avg. yield (kg/ha)||Value ($1,000,000)|
|Selected essential oils||Quantity |
|Value of |
|Anise oil||49||0.6||China, Spain, France|
|Bergamot oil||53||2.2||Italy, France, FRG|
|Camphor oil||33||0.2||Taiwan, China, France|
|Caraway oil||8||0.2||Netherlands, France, Poland|
|Cedar leaf oil||32||1.5||Canada|
|Cedarwood oil||720||2.2||China, Hong Kong|
|Citronella oil||517||4.9||China, Taiwan, Argentina|
|Citrus oils, other||53||0.6||Mexico, Brazil|
|Comment oil (Mentha arvensis)||273||2.5||China, Brazil, England|
|Eucalyptus oil||312||1.9||China, Australia, Brazil|
|Geranium oil||83||3.5||France, China, Egypt|
|Grapefruit oil||85||1.2||Brazil, Israel, Belize|
|Lavender oil (inc. spike)||75||1.3||France, Spain, Bulgaria|
|Lemon oil||744||10.2||Argentina, Spain, Italy|
|Lemongrass oil||74||0.9||Guatemala, India|
|Lignaloe (Bois de rose oil)||53||1.3||Brazil, France|
|Lime oil||870||13.0||Mexico, Peru, Brazil|
|Neroli (orange flower oil)||1||0.5||France, FRG|
|Onion and Garlic oil||13||1.3||Mexico, Egypt Netherlands|
|Orange oil||5,684||8.8||Brazil, Mexico, Israel|
|Origanum oil||7||0.3||Spain, France|
|Orris oil||2||1.1||FRG, France|
|Palmarosa oil||15||0.4||India, Guatemala, Brazil|
|Peppermint oil (mentha x piperita)||13||0.4||Hong Kong, France|
|Petitgrain oil||119||2.3||Paraguay, Brazil|
|Pineneedle oil||257||1.0||Mexico, Canada|
|Rose oil (Attar of roses)||2||8.7||France, Turkey, Brazil|
|Rosemary oil||48||0.5||Spain France, Tunisia|
|Sassafras oil||344||1.6||Brazil, China|
|Spearmint oil||69||0.8||China, Hong Kong|
|Thyme oil||14||0.5||Spain, France|
|Vetiver oil||96||6.0||Haiti, Indonesia, France|
|Ylang ylang (Cananga oil)||41||2.7||France, Comoros, Indonesia|
|Other essential oils||1,545||40.0||France, China, Brazil|
|Essential oils||Quantity |
|Cedarwood, clove & nutmeg oils||660||4.5|
|Item||Quantity (MT)||Value |
|Anise||767||1.4||Spain, Turkey, Egypt|
|Capsicum/Red peppersz||10,169||14.0||Pakistan, China, Mexico, India|
|Caraway||2,838||2.4||Netherlands, Egypt Poland|
|Coriandery||5,938||3.3||Mexico, Morocco, Romania|
|Fennel||1,754||1.8||Egypt, India, China|
|Gingerx||5,054||4.6||Fiji, Brazil, China|
|Mint leavesz||172||0.6||FRG, Egypt|
|Onions (dried, dehydrated)||107||<0.1||Canada|
|Origanum||3,837||7.2||Mexico, Turkey Greece|
|Rosemary||810||0.7||Spain, France, Yugoslavia|
|Sesame seed||33,146||25.7||Mexico, Guatemala, El Salvador|
|Tarragon||62||0.6||France, New Zealand|
|Thyme||956||2.1||Spain, Jamaica, Morocco|
|Mixed spices, others||2,473||6.7||India, Morocco, Thailand|
|Dill weed||Anethum graveolens L.||70|
|Clary sage||Salvia sclarea L.||5|
|Perennial wormwood||Artemisia absinthium L.||3|
|Basil||Ocimum basilicum L.||1|
|Wormseed||Chenopodium ambrosioides L.||1|
|Tansy||Tanacetum vulgare L.||0.5|
|Snakeroot (Canadian)||Asarum canadense L.y||0.1|
|Celery herb||Apium graveolens L.||nax|
|Celery seed||Apium graveolens L.||na|
|Marigold||Tagetes minuta L.||na|
|Parsley herb||Petroselinum crispum (Mill.) Nym ex A. W. Hill||na|
|Angelica||Angelica archangelica L.|
|Anise||Pimpinella anisum L.|
|Caraway||Carum carvi L.|
|Chervil||Anthriscus cerefolium (L.) Hoffm.|
|Cilantro||Coriandrum sativum L. (see coriander)|
|Coriander||Coriandrum sativum L.|
|Cumin||Cuminum cyminum L.|
|Dill||Anethum graveolens L.|
|Fennel||Foeniculum vulgare Mill.|
|Lovage||Levisticum officinale Koch|
|Mitsuba||Cryptotaenia japonica Hassk.|
|Parsley||Petroselinum crispum (Mill.) Nym. ex A. W. Hill|
|Chamomile||Chamaemelum nobile (L.) All (Roman)|
|Chamomilla recutita (L.) Rauschert (German)|
|Chicory||Cichorium intybus L.|
|Chrysanthemum (edible) or Chopsuey greens||Chrysanthemum coronarium L.|
|Costmary||Balsamita major Desf.|
|Curry Plant||Helichrysum angustifolium (Lam.) DC|
|Dandelion||Taraxacum officinale G. H. Weber|
|French Tarragon||Artemisia dracunculus L.|
|Borage||Borago officinalis L.|
|Arrugula or rocket salad||Eruca vesicaria (L.) Cav. ssp. saliva (Mill.) Thell|
|American||Armoracia rusticana P. Gaertn.|
|Japanese||Wasabia japonica (Miq.) Matsumura|
|Black||Brassica juncea (L.) Czern.|
|Brown||Brassica nigra (L.) W. Koch|
|White||Sinapsis alba L.|
|Pepper grass or garden cress||Lepidium sativum L.|
|Watercress||Nasturtium officinale R. Br.|
|Capers||Capparis spinosa L.|
|Saffron||Crocus sativus L.|
|Anise-hyssop||Agastache foeniculum (Pursh) Kuntze|
|Hyssop||Hyssopus officinalis L.|
|Korean mint||Agastache rugosa (Fisch. & C. A. Mey) Kuntze|
|Lemon balm||Melissa officinalis L.|
|Peppermint||Mentha x piperita|
|Native spearmint||Mentha spicata L.|
|Scotch spearmint||Mentha x gracilis Sole|
|Marjoram||Origanum marjorana L.|
|Oregano||Origanum vulgare L.|
|Rosemary||Rosmarinus officinalis L.|
|Sage||Salvia officinalis L.|
|Savory||Satureja hortensis L. (summer savory)|
|Satureja montana L. (winter savory)|
|Bay Laurel||Laurus nobilis L.|
|Chives||Allium schoenoprasum L.|
|Chinese chives||Allium tuberosum Rattler ex Spreng.|
|Garlic||Allium sativum L.|
|Kurrat||Allium kurrat Schweinf. ex K Krause|
|Leeks||Allium ampeloprasum, Porrum group|
|Shallots||Allium cepa, Aggregatum group|
|Sorrel||Rumex acetosa L.|
|Black cumin||Nigella sativa L.|
|Burnet||Sanguisorba minor Scop.|
|Rue||Ruta graveolens L.|
|Lemon verbena||Aloysia triphylla (L'her.) Britton|
|Mexican oregano||Lippia spp.|