What is the Cakile maritima or sea caterpillar?
Maritime Cakile, commonly known as sea caterpillar, sea radish, maritime rocket o persimmon, is an annual herbaceous plant belonging to the Brassicaceae familyIts presence is characteristic of European beaches and coastal dunes, where it stands out for its pioneering role, its resistance to adverse conditions, and its importance in the formation and stabilization of coastal ecosystems.
It is easily recognized by its low and extended stature, its greenish color with sometimes magenta tones, and its four-petaled flowers, ranging from white to lilac. This plant plays a fundamental role in the colonization of sandy environments, participating in ecological succession and serving as a refuge and food for various species.
Vernacular names and etymology
Cakile maritima is known by a variety of names in different regions and languages. In Spanish, it is called sea caterpillar, sea radish, maritime rocket, rejoncillos, sea ruca o rucamar. In Portuguese as marine eruca; in Galician, persimmon o sea eiruga; in Catalan, sea urchin; and similar variants exist in other European languages.
The generic name comes from Arabic kakeleh o qaqila, referring to this plant. Its specific epithet, marine, refers to its habitat by the sea.
Botanical description and morphology
Maritime Cakile It is an annual plant, hairless and robust in appearance, which can have prostrate or erect stems, branched and succulent during the early stages of development. It can reach between 15 and 45 cm in height, although in optimal environments it forms small clumps of up to 1 meter wide.
The leaves are alternate, light green or glaucous, fleshy, and adapted to limit transpiration, resisting environmental salinity. The lower leaves (3-6 cm) are usually petiolate and obovate to pinnatifid, with entire or toothed lobes, while the upper leaves are generally entire and sessile.
Flowers appear most of the year, but especially in the warmer months. They appear in dense clusters on both the central stem and the lateral branches. Each flower has four narrow sepals, yellowish-green in color, and four spatulate petals with claws, in shades of white, lilac, or purple. The androecium is composed of six tetradynamous stamens (four long and two short).
The fruit is a indehiscent silique, bilobed, 20-25 mm long, formed by two distinct monospermous segments. The upper segment, larger in size, is ovoid or conical and detaches for long-distance dispersal, floating on the water. The lower segment remains attached to the parent plant and facilitates local seed dispersal. The seeds are oblong, brown, rough, and adapted to float, allowing the colonization of new coastal areas.
Life cycle and reproduction
The sea caterpillar It is an annual plant. It germinates after storms and rains wash away the salts from the substrate, taking advantage of the increased humidity and the contribution of nutrients derived from organic debris carried by the sea (particularly algae). Its reproduction depends exclusively on seeds, since the plant's lifespan in the field is usually short, just a few months. Under normal conditions, the plant flowers and bears fruit quickly before dying, leaving abundant offspring that will germinate the following year.
An interesting aspect is the particular arrangement of its fruits, which allows for a dual dispersal strategy: the upper segment facilitates colonization of other shores thanks to its buoyancy, while the lower segment favors permanence on the beach or dune of origin, contributing to the formation of small population centers.
Geographical distribution
Maritime Cakile It is native to the Atlantic, Mediterranean, and Black Sea coasts. It ranges from Morocco and North Africa to Scandinavia, the Baltic Sea, and the Canary Islands, with confirmed presence in much of Western, Central, and Northern Europe. It has subsequently become naturalized in the Americas and Australia, regions where it is sometimes considered an invasive species due to its strong colonizing capacity.
In addition, there are geographically differentiated subspecies, such as Cakile maritima subsp. maritime in the Atlantic and Mediterranean, subsp. baltica in the Baltic, subsp. euxina in the Black Sea area and subsp. islandica in the Arctic regions of Norway, Iceland and Russia.
Habitat and ecology
The sea caterpillar It is a pioneer species native to sandy coastal environments exposed to the action of wind and tides. Its ecological range extends from the areas most exposed to waves, barely covered by vegetation and near the high tide line, up to interior areas of still-moving dunes. It tends to thrive in accumulations of organic debris (especially algae and reeds), where the nitrogen supply encourages its rapid and vigorous development.
It stands out for its ability to tolerate high levels of salinity, strong winds, long periods of drought, and soils poor in organic matter. Its taproot, which can reach up to 40 cm deep, allows access to subsurface water reserves. Furthermore, its fleshy, thickened leaves ensure efficient water retention, optimizing survival under water stress conditions.
This plant plays a fundamental role in the stabilization and formation of coastal dunes by binding sand and reducing erosion. It also participates in the formation of pioneer communities alongside other halophilic species such as Kali Salsola, which has led to its habitat being considered as being of community interest in European environmental regulations.
Adaptations to the coastal environment
- Salt tolerance: The succulent leaves, covered with a thick cuticle, prevent excessive water loss and resist salt buildup.
- Water retention: The fleshy texture of its stems and leaves allows it to survive periods of drought, common on beaches and dunes.
- Dispersal by sea: The seeds and seedpods float easily, colonizing new beaches, which favors their wide distribution and ability to form new populations after storms and spring tides.
- Rapid growth: Its accelerated development takes advantage of the nutrients available after the decomposition of organic matter deposited by the sea.
Ecological importance and plant associations
Cakile maritime is essential for the ecological succession of coastal dune environmentsIts roots help to fix the sand, facilitating subsequent colonization by other perennial plants and contributing to the creation of stable dunes. Furthermore, its immature fruits are a food source for numerous herbivores, such as rabbits and small rodents.
In habitats where it coexists with Kali SalsolaBoth form unique protected plant communities, called "Annual Vegetation on Accumulated Marine Debris" by European Union environmental regulations.
Diversity and similar species
There are other species within the genus Cakile, but none share exactly the same ecological range or the particular adaptations of the sea caterpillar. Therefore, it is very unlikely to be confused with other species in its natural environment. However, in North American coastal areas, the replacement of native species by Maritime Cakile where it has been introduced.
Flowering and fruiting
Cakile maritima blooms most of the year in temperate, coastal climates. The flower clusters emerge primarily between spring and autumn, although flowers can be observed even during the less warm months, depending on latitude and local conditions. Fruiting is equally prolonged, and the seeds can be dispersed at different times, coinciding with periods of rain or storms.
Medicinal and food uses
The sea caterpillar has been traditionally used for medicinal and food purposes., especially in times of scarcity and in coastal communities.
- Medicinal properties: The fresh plant, especially its leaves, is rich in Vitamin C and has traditionally been used as an antiscorbutic remedy. The juice of fresh leaves, strained and sweetened, has been used as a remedy for bronchial catarrh and, externally, as a wound healing agent. However, its medicinal use is very limited today.
- Nutritional properties: The young leaves can be eaten raw in salads, although their flavor is noticeably bitter and salty. The tender stems, after cooking, are also suitable for consumption and were formerly used to flavor stews. The roots, dried and ground, have been mixed with flour to make bread in times of famine. The seeds contain oils similar to those of mustard (Sinapis alba).
- Cosmetic and traditional uses: Infusions of leaves have been used to treat oily skin and decoctions of flowers have been used as an anti-dandruff product.
To delve into the species that can accompany the pioneer vegetation in dunes, you may be interested in learning more about plants adapted to similar environments.
Nutritional value
The aerial parts of the sea caterpillar contain a high level of vitamin C, Although its nutritional value beyond this aspect is low, it is not considered a widely used vegetable. Its flavor is intensely bitter and salty, which limits its current culinary use except as a botanical curiosity in wild salads.
Care and cultivation of Cakile maritima
Although the sea caterpillar is primarily a wild plant found in coastal environments, it is possible to cultivate it in coastal-inspired gardens or dune restoration projects. To achieve this, it is essential to mimic its natural habitat:
- Substratum: Sand or very well-drained sandy soil, with some organic content (decomposed plant remains) to provide nitrogen.
- Light: Full sun. Tolerates strong winds, direct exposure, and the solar reflectance typical of coastal environments.
- Irrigation: Very little or no growth once established, except during periods of intense drought. It does not tolerate waterlogged soils.
- Salinity: Resists saline soils and marine sprays.
- Sowing: Best done directly in the field, in late winter or early spring, mimicking natural conditions after rain and storms.
- Spacing: Space seedlings at least 20-30 cm apart. Because it grows quickly and branches, it can cover surfaces as part of a dune restoration system.
- Fertilizer: It does not require additional fertilization, although it appreciates the addition of organic matter from plant remains.
To facilitate its establishment, it is also recommended to consult techniques of cultivation in coastal environments.
Impact and threats
Maritime Cakile It is exposed to various threats in its natural environment, such as the destruction of coastal habitats, beach development, the constant movement of people, vehicles, and machinery, and the removal of organic waste (algae and reeds), which constitute its main source of nutrients. Furthermore, climate change and the retreat of dunes increase the risk to its populations.
Due to its ecological importance, many of the areas where it grows are included in environmental protection agreements and dune and beach restoration and management strategies. It is essential that human activities respect these areas to prevent the loss of biodiversity and associated ecosystem services.
Interesting facts and curiosities
- It blooms most of the year in temperate climates, providing food for pollinating insects.
- Their seeds can travel several kilometers floating in the sea before colonizing new beaches.
- Participate in pioneering plant communities alongside Kali Salsola, providing important habitats for coastal fauna.
- Leaf extracts have been tested in natural cosmetics for skin care.
- In some places, the sea caterpillar is a symbol of resilience and extreme physiological adaptation.
Taxonomic classification
- Domain: eukarya
- Supergroup: Archaeplastida
- Division: Streptophyta
- Class: Magnoliopside
- Order: brassicales
- Family: Brassicaceae (Cruciferae)
- Gender: Cakile
- Species: Cakile maritima Scop.
The chromosome number is constant (2n = 18) and the taxonomic classification may vary depending on new research. Its botanical synonyms include Bunias cakile, Cakile cakile and others collected in regional floras.
Glossary of relevant botanical terms
- Silicua: Typical dried fruit of cruciferous vegetables, longer than it is wide.
- Petiolate: With a petiole or stalk that joins the leaf to the stem.
- Tetramers: Flowers with four petals and sepals.
- Procumbent: Stem prostrate or creeping, although with ascending apices.
- Glaucous: Coloration between light green and blue.
- Oblong: Organ longer than it is wide, in this case the seeds.
FAQs
- Is the sea caterpillar toxic? It is not considered toxic, but its bitter taste limits its culinary use. There are no records of significant toxicity to humans or pets.
- Can it be grown far from the coast? It requires well-drained sandy soils, maximum sunlight exposure, and very sporadic watering; its cultivation is more difficult outside coastal environments, except in xerophilous or ecologically restored gardens.
- What functions does it have in nature? It protects and stabilizes dunes, colonizes disturbed areas, provides food and shelter to wildlife, and promotes plant succession in highly dynamic areas.
The sea caterpillar, Maritime CakileIt is a plant exceptionally well adapted to the most extreme coastal environments. Its rapid and efficient life cycle, resistance to salinity and drought, and its important ecological role as a stabilizer and pioneer make it a true symbol of coastal biodiversity. Respecting and conserving this species is equivalent to protecting an entire ecosystem and the richness of the European and Mediterranean coasts.