Physalis philadelphica, commonly known as tomatillo, husk tomato, green tomato or milpa tomato, is an emblematic plant for the agricultural, gastronomic, and cultural diversity of Mesoamerica, especially Mexico. Its small, paper-lantern-like fruit has been a fundamental part of both traditional cuisine and folk medicine for centuries, and its cultivation represents a significant part of the region's biocultural heritage.
Taxonomy and common names
- Scientific name: Physalis philadelphica Lam.
- Other scientific names: Physalis aequata Jacq., Physalis ixocarpa Brot. former Horn.
- Family: Solanaceae
- Spanish names: Tomatillo, husk tomato, green tomato, milpa tomato, miltomate (when referring to small varieties)
- English names: Husk tomato, Mexican ground-cherry, tomatillo
Notes on taxonomy: There are various taxonomic schools of thought that debate the synonymy between Physalis philadelphica, P. ixocarpa and P. aequata, attributing to them in some cases species differences and in others, intraspecific variability.
Higher taxonomic categories:
- Kingdom: Plantae
- Subkingdom: Tracheobionta
- Superdivision: Spermatophyta
- Division: Magnoliophyta
- Class: Magnoliopsida
- Subclass: Asteridae
- Order: Solanales
Origin, domestication and geographical distribution
Physalis philadelphica is native to Mesoamerica, with Mexico as the center of diversity and domestication.It has been recorded since pre-Hispanic times and has been part of indigenous cultures in traditional food and medicine. Its primary distribution is Mexico, extending to the United States, Central America, and the Antilles. Currently, it is present both in the wild and cultivated in numerous countries and regions around the world, adapting well to different climates and soils.
- In Mexico: It is reported in almost all states, from Baja California to Veracruz, covering temperate, warm, and subtropical climate zones.
- International distribution: The tomatillo is grown in Central America and has become known and used in various cuisines throughout the Americas and even in Europe and Asia, where it is appreciated for its flavor and versatility.
This species has a great capacity to grow both in cultivation and in the wild, and is often found in home gardens, traditional cornfields, and areas of disturbed vegetation.
Botanical identification and description
Physalis philadelphica It is an erect, branched, annual herbaceous plant that typically reaches heights of between 15 and 60 cm. It has very distinctive morphological characteristics that make it easy to identify:
- Stem: Erect, with branches, generally glabrous or with scattered hairs.
- Sheets: Alternate, ovate, with irregularly toothed margins, attenuate base, petioles 0.4 to 6.5 cm long.
- Flowers: Solitary, with a yellow corolla and sometimes bluish or violet markings. Short peduncle (0.7 to 1 cm). Blue or blue-green anthers.
- Chalice: Enlarged, lantern-shaped, completely enveloping the fruit during development, with 10 well-marked ribs.
- Fruit: Spherical or slightly flattened berry, 1.6 to 6 cm in diameter, contained within the calyx. The color is generally green, but can vary to yellow or purple in certain varieties.
- Seeds: Obovate, circular or kidney-shaped, compressed, yellow to brown, reticulated surface.
The life cycle of this plant is annual, completing its development from germination to fruiting in a single agricultural season, although it can flower and bear fruit throughout the year if temperature and humidity conditions allow it.
Habitat and growing conditions
The tomatillo is highly adaptable and is commonly found in various habitats:
- Roadsides and ditches
- Milpas and irrigated or rainfed crop fields
- Areas with moderate humidity, as well as disturbed soils
You can find Physalis philadelphica from sea level to altitudes of over 2000 meters., demonstrating its ecological flexibility. It prefers well-drained soils with full sun exposure, although it tolerates various soil types and is less susceptible to pests than other solanaceous plants such as tomatoes or eggplants. It's important to mention that for proper development and fruiting, it's recommended to plant at least two plants to ensure pollination, as the species exhibits floral self-incompatibility.
Notes on home growing: Growing tomatillos is easy, ideal for both urban and traditional gardens. The plant typically flowers over a long period, producing fruit continuously as long as conditions permit.
Biology, ecology and genetic diversity
Physalis philadelphica It is characterized by its annual cycle and its ability to produce multiple fruits throughout the entire growing season. The plant displays great genetic diversity, which translates into a wide variability in fruit shapes, colors, and sizes, as well as differences in flavor and concentration of bioactive compounds.
Numerous local or native varieties have been recorded, each adapted to specific climate or agricultural management conditions. This diversity is crucial for food security and resilience to disease and environmental changes.
Pollination requires the presence of pollinating insects, and since it is self-incompatible, it requires planting more than one individual to ensure fruit production. The tomatillo is also capable of forming part of complex agroecosystems, interacting with other economically and culturally important crops, such as corn and chili.
Agricultural impact and associated crops
Physalis philadelphica It can be found both as a main crop and as a weed in fields of alfalfa, cotton, coffee, beans, broad beans, other vegetables, corn, cactus, and tomatoes. In some agricultural contexts, it has been recorded as an unintentional companion species, although its presence is often exploited for its nutritional and medicinal value.
Culinary uses and organoleptic properties
The main use of Physalis philadelphica is gastronomic. The tomatillo is an essential ingredient in many traditional mexican dishes:
- Green sauce base: It adds acidity and freshness to sauces that accompany tacos, enchiladas, chilaquiles, and stews.
- Stews and soups: It is a great addition to broths, moles, and soups for its slightly acidic flavor and ability to enhance other ingredients, especially chili and corn.
- Contemporary dishes: Its versatility allows it to be used in innovative recipes, salads, ceviches and as a garnish.
The flavor of tomatillo can be described as sweet and sour and refreshing, with a characteristic acidity that helps balance the pungency of the spice in traditional Mexican food.
Medicinal uses and traditional exploitation
Physalis philadelphica has a long history of use in traditional indigenous and folk medicine:
- Fruits: Used to relieve fever, cough and tonsillitis.
- Sheets: Remedy for gastrointestinal disorders when used as an infusion.
- Chalice: The membrane surrounding the fruit is used in infusions to help reduce blood sugar levels and blood pressure.
Compounds known as have been identified in the fruit and leaves Physalis (with antimicrobial effects) and withanolides (natural steroids). It is worth noting the ixocarpalactone A (IxoA), a compound exclusive to green tomatillos that has been studied for its potential chemoprotective effect against certain types of cancer, such as colon cancer.
Nutritional value and bioactive compounds
Tomatillo is considered a functional food due to its contribution of various essential nutrients and phytochemical compounds. From a nutritional standpoint, Physalis philadelphica provides:
- Vitamin C:
- Niacin (vitamin B3)
- Minerals such as calcium and phosphorus
- Dietary fiber
- Antioxidants
Although its nutrient concentration is not high compared to other fruits, including it in the diet promotes dietary diversity, providing flavor, texture, and health-promoting compounds. It's recommended to eat it alongside other vegetables to meet daily needs and add variety to dishes.
The presence of has been verified Four types of withanolides exclusive to Physalis, compounds of great interest due to their biological action, in addition to physalins with proven antimicrobial and anti-inflammatory effects. Recent studies support the pharmacological potential of these components for the development of new drugs.
Cultivation and agronomic management
Physalis philadelphica is easy to grow and adapts well to different driving conditions:
- Planting method: Directly in the field or in a seedbed for transplanting.
- Soil requirements: It prefers light, well-aerated and well-drained soils, although it tolerates poor soils.
- Exhibition: Full sun.
- Irrigation: Moderate, avoiding waterlogging.
- Self-incompatibility: Need to plant at least two plants to ensure fruit production.
The plant can be grown as an annual, renewing its production each crop year. It is also prized as an ornamental plant due to the distinctive shape of its calyx. Its cycle can be extended as long as the temperature does not drop below 10°C, allowing for multiple harvests in a single year in warm climates.
Cultural importance and biodiversity
Physalis philadelphica is an integral part of the food and agricultural culture of Mesoamerica.Its domestication and continued use in traditional farming systems—such as the milpa—have been fundamental to the subsistence and dietary diversity of rural communities, as well as to the resilience of their agroecosystems. It also strengthens the region's culinary identity worldwide.
Physalis's relationship with other crops in the milpa (corn, beans, chili, squash) demonstrates the importance of polycultures for natural resource management and food sovereignty. Its local varieties, developed over centuries, are a valuable genetic reservoir in the face of global challenges such as climate change and genetic erosion.
Links, sources and additional resources
- Physalis philadelphica fact sheet at CONABIO
- What green tomatoes provide us (Mexican Biodiversity)
- What is tomatillo? (CRJ Produce)
