sea medic, popularly known as beach cart, sea clover, sea dogfish, beach grass y silver grass, is an emblematic plant of Mediterranean and Atlantic coastal landscapes. In coastal ecosystems, where sandy and saline soils, gusty winds, and scarcity of freshwater make survival a real challenge, this species stands out for its incredible adaptability.
Botanical description and morphology of Medicago marina
sea medic is a perennial herb which can reach dimensions between 10 and 50 centimeters in length. Its stems, prostrate or slightly ascending at the end, are robust, woody at the base and usually have modest branching. The entire plant is easily recognized by its whitish or greenish-gray hue, a result of its dense woolly garment, a distinctive feature that gives it a velvety appearance and a soft texture to the touch. This hairy covering, made up of long, non-glandular hairs, serves the essential function of protecting the plant from drying out, wind, and excessive solar radiation.
Leaves They are arranged alternately and are trifoliate, that is, each leaf consists of three broad, fleshy leaflets, between 5 and 12 mm long and obovate or flabellate in shape. The margin of the leaflets can be entire, serrate or slightly toothed, with rounded, retuse or apiculate apices. Both sides of the leaflets and their buds show dense, silky hairs. stipules, located at the base of the petiole, are ovate or lanceolate, acuminate and may have entire or toothed margins, of a straw-colored color.
El root system The root of Medicago marina is deep and firm, typical of plants adapted to dunes and marine gravel. This root allows a solid anchorage in loose and sandy soils, as well as the efficient capture of moisture in depth, overcoming the surface desiccation typical of these environments.
Its morphology distinguishes it from other legumes in its habitat, such as lotus creticus, with which it often coexists. While Lotus pods are straight, Medicago marina's flowers are spiral-shaped, and its hairiness is much more pronounced, making it unmistakable to attentive observers.
Biological cycle: flowering and fruiting of the beach wagon
The period of flowering Medicago marina's season ranges from late winter to mid-summer, mainly from February to July, although it can be longer in certain regions depending on the climate. The small yellow flowers, hermaphroditic and zygomorphic, are grouped in capitate inflorescences or dense glomeruli of between 5 and 15 units located in the axils of the leaves, with peduncles that can exceed the length of the adjacent leaf petiole.
Each flower shows the typical "butterfly" morphology of the Fabaceae: consists of a banner large and wide (the upper petal more showy), two alas lateral and two lower petals fused together to form the quillThe corolla (6-9 mm) is a deep yellow, whose brilliance is striking in contrast to the light color of the plant. The calyx is campanulate, with five almost identical teeth, exceeding 2 mm in length.
Pollination gives rise to the characteristic spiral fruitsThese pods are indehiscent, strongly woolly, 4 to 6 mm in diameter, coiled in spirals of 2 to 4 turns and densely covered with hairs. They usually have two rows of short, conical spines (up to 1,5 mm), although they may occasionally be reduced to tubercles. The fruit protrudes from the calyx and acquires a straw-colored color as it ripens.
The kidney-shaped seeds, up to 3 mm in size, are brown and protected by the dense structure of the fruit. This design facilitates dispersal through epizoochoric mechanisms: the fruits can adhere to the fur of animals, which carry them to new locations.
Taxonomic classification and etymology of Medicago marina
- Reino: plant
- Division: Magnoliophyta (flowering plants)
- ClassMagnoliopsida (dicotyledons)
- Order: Fabales
- FamilyFabaceae (legumes or papilionaceae)
- Subfamily: Faboideae
- Tribe: Trifolieae
- Gender: Medicago
- Species: Medicago marina
Name Medicago It comes from the Latin medical, in turn from the ancient Greek μηδική (medikos), referring to "herb native to Media" (historical region of Iran), while marina It refers to its coastal habitat, being a Latin epithet meaning "of the sea" or "related to the sea."
Medicago marina was formally described by Carl Linnaeus in the work Species Plantarum. It has a chromosome number of 2n=16. In addition, there are several synonyms and infraspecific taxa that can be found in the botanical literature, such as Marine doctor (L.) Lam., Medica tomentosa Moench, Maritime Medicine Bubani, among others, reflecting the morphological and taxonomic diversity of this species.
Habitat, ecology and geographical distribution
sea medic It is a real specialist in coastal environments. Preferably inhabits dunes and coastal sandbanks (white, grey and secondary), but can also be found in marine gravels, from sea level to about 50 metres above sea level. It is characteristic of areas with sandy soils, poor in nutrients, high salinity and variable humidity.
The natural distribution of Medicago marina includes the entire Mediterranean region, from Southern Europe and North Africa to Western Asia. It also colonizes the Black Sea coast, the Atlantic coast of southwest Europe (as far south as Brittany, France), and has been introduced to the Canary Islands. In the Iberian Peninsula, it is common throughout the entire coastal zone, both in the Mediterranean and the South Atlantic, and its presence has been confirmed in all the coastal provinces of Galicia.
Its altitudinal range is restricted, as it barely penetrates inland, remaining attached to the dune systems. It prefers locations where the dune systems are well preserved, and is sensitive to alteration, erosion, or urbanization of these environments. Furthermore, does not tolerate shade and requires full sun exposure, making it a clear example of a heliophilous species. You can find more information in our article. All about Medicago marina beach wagon.
From an ecological perspective, the presence of Medicago marina is an indicator of the good health of dune habitatsIts deep, branched root system contributes decisively to the fixation of the sandy substrate, slowing wind erosion and playing an essential part in the stabilization process of secondary and gray dunes. It is also frequently associated with other pioneers such as ammophila arenaria, vital for the initial fixation of dunes.
Ecological indicators, adaptations and relationships with other species
sea medic It presents remarkable adaptations to life in extreme conditions. According to Ellenberg's ecological indicators, it is a species that:
- It requires light and does not tolerate shade.
- Prefers soils of moderately dry to humid
- It settles on substrates rich in bases and with a pH between 5.5 and 8, which makes it an alkalinity indicator
- Tends to thrive in nutrient rich soils, although it can tolerate infertile environments
- It has a high tolerance to salinity typical of coastal ecosystems
his way of seed dispersal It is predominantly epizoochorous, meaning the spiny, woolly fruits easily adhere to animal fur, thus extending its range. The average seed weight is 4.1 mg, and the plant typically grows to a height of around 20 cm.
As for its biological form, it can be classified as camephyte (plants with winter buds located above the ground, but less than 25 cm high) and occasionally as a hemicryptophyte (buds at or just below ground level).
sea medic It maintains diverse community interactions. It promotes the proliferation of pollinating insects, especially bees and beetles, and can serve as a refuge for small invertebrates. It also constitutes part of the plant associations that form the most advanced dune communities (grey or stabilized dunes).
Conservation status and threats
Although the population trend is stable and its conservation category in Spain is usually "Least Concern (LC)" according to the IUCN, there are regions where sea medic It is listed as a protected species or sensitive to habitat alteration. Of note are the regional classifications of Asturias (sensitive species), Cantabria (endangered), and other areas where tourist pressure, construction, and recreational beach use seriously affect dune systems.
The main threat factors include:
- Alteration and destruction of dunes by urbanization and human activities
- Excessive vehicle traffic and trampling on natural beaches
- Strong tourist and recreational pressure on the coast
- Changes in vegetation due to the invasion of exotic or competing species
The conservation of Medicago marina is linked to the preservation of dune systems, and is a clear indicator of biodiversity and coastal ecological balance.
Uses, properties and ecological value
Medicago marina has no agricultural, livestock or traditional medicinal uses., unlike alfalfa (medicago sativa). The dense hairiness, small size and specialization for coastal environments make its conventional productive use unviable.
However, its ecological importance is outstanding:
- Contribute to fix soils and control wind erosion in unstable environments
- It favors the biodiversity, acting as a refuge and resource for pollinators and small animals
- In restoration gardening and coastal xeriscaping, It can be used as a long-lived ground cover plant
- It is ideal for dune habitat restoration projects and for sustainable coastal gardens where low water requirements and rusticity are competitive advantages.
Furthermore, its presence is associated with plant communities in a good state of conservation and is a bioindicator useful for environmental studies in coastal areas.
Growing and caring for Medicago marina in gardening
If you live near the coast, have light soils or want to give a native and sustainable touch to your garden, Growing Medicago marina is an excellent choiceThese are the main aspects to consider for your success:
- Siembra: Sow in spring, using a universal substrate in seedbeds or trays, and lightly cover the seeds. Place a maximum of two seeds per socket.
- Environmental conditions: Prioritize a location to full sunShade has a negative impact on the vigour and flowering of the species.
- Plantation: When the seedlings show visible roots, transplant them into the soil leaving a distance of at least 55 cm, to allow for the natural expansion of the stems.
- IrrigationModerate. In summer or during dry periods, water every 2-3 days. The rest of the year, the frequency can be significantly reduced.
- Subscriber: It's not strictly necessary. You can apply worm castings or compost during transplanting to encourage good rooting.
- AftercareOnce established, it requires little maintenance, resisting both drought and salinity and poor soil.
Ideal for xeriscaping and dune restoration, Medicago marina adapts optimally to environments where other species fail, providing natural beauty with its bright yellow flowers.
Key differences between Medicago marina and Medicago sativa (alfalfa)
It is essential not to confuse sea medic with the well-known alfalfa (medicago sativa), despite belonging to the same genus. Here are some key differences:
- Habitat and appearanceMedicago marina has a creeping and pubescent appearance, typical of sandy coastal soils; Medicago sativa is erect or suberect, with thin, less hairy stems and grows in agricultural fields.
- DimensionsMedicago marina reaches up to 50 cm in lateral spread; Medicago sativa can reach 60 cm in vertical height.
- FloresMedicago marina blooms in yellow glomeruli; alfalfa presents lilac or purple bunches.
- FruitsMedicago marina legumes are dense, woolly spirals; those of alfalfa are simpler spirals and not very hairy.
- Use: Alfalfa is a forage crops of great value; Medicago marina has no direct agricultural use, but is vital for dune conservation.
Common names and curiosities
Medicago marina has multiple names in Spanish-speaking regions and in other languages:
- Beach cart (Spanish)
- Sea dogfish, dogfish, silver grass, sea clover (Spanish)
- Erva-cordeira, grass-areas (Portuguese)
- Beach Lucerne, sea witch (Galician)
- Sea falç, clover marí (Catalan)
Its spiral-shaped fruits, often covered in thorns, have long attracted attention and have been the subject of study in traditional botanical systems. This morphological and adaptive uniqueness makes Medicago marina a benchmark for botanists and coastal flora enthusiasts.
Knowledge of the biology and ecology of sea medic It allows us to appreciate the importance of protecting coastal habitats and maintaining biodiversity. Their presence is a sign of a well-preserved coastline and an invitation to discover the fascinating adaptations of Mediterranean and Atlantic flora.
