PLANT OF THE MONTH __ SEPTEMBER 2025
Cladium mariscus subsp. mariscus (L.) Pohl
CAT: Sesquera (sometimes also referred to as Erianthus ravennae), xisca or sesca borda, serret, sega-mans, talla-mans, mansega, jonc morisc.
EN: great fen-sedge, swamp sawgrass (common names vary by region; “masiega” is not commonly used in English).
FAMILY: CYPERACEAE
Synonyms: Mariscus mariscus (L.) Borbás; Schoenus mariscus L.
DISTRIBUTION:
There are four subspecies: one found in California, Mexico, and Texas; another in Australia and New Caledonia; one more in tropical and subtropical America; and the European subspecies, which extends to the Azores, North Africa, the Caucasus, and the temperate regions of the Himalayas. This subspecies, specifically in the Balearic Islands, is found on all four major islands.
CONSERVATION STATUS:
It is a protected species classified as LC (Least Concern). The main threat to this species is the loss of its habitat. Wetlands in the Balearic Islands—and in general—are threatened habitats, impacted by land-use changes and also by climate change, among other factors.
PHENOLOGY:
It flowers in spring and bears fruit in autumn, starting in September.
LIFE FORM:
Geophyte.
HABITAT:
It grows on the edges of wetlands and flooded meadows, in nutrient-rich waters, and it can sometimes tolerate a certain level of salinity. It forms part of a vital habitat for many species living in freshwater wetland environments.
DESCRIPTION:
“Sesquera” or “sesca borda” are traditional Catalan terms used to describe graminoid wetland plants. In old Catalan, sesca refers to a long, dry-stemmed plant used for kindling or making mats.
Cladium mariscus is a tall, perennial herb with glaucous, tough, rigid leaves that have serrated and sharp edges. Its roots form a highly branched underground rhizome, allowing the plant to spread if it finds a suitably moist habitat.
The flowers are grouped in a terminal spike-shaped inflorescence, and the stems—like all in the Cyperaceae family—are triangular in cross-section at the upper part.
The fruit is an ovoid-trigonous achene, just over 3 mm long, shiny brown in color, with the persistent base of the style, as shown in the photographs in the book “Diàspores. Fruits de llavors de la flora Balear” by Gradaille and Bonet (2022).
This species is preserved in the collections of the Botanical Garden: the seeds were collected from the population at s’Albufera, and the plants currently on display in the Garden come from the Canyamel stream (Capdepera). In addition, herbarium specimens are preserved from these populations as well as from others that have since disappeared, such as those in Sóller or Alconàsser. In these cases, the herbarium sheets serve as a historical record of the vegetation that could be found in these wetlands between 1910 and 1918.
