Najas marina
Najas marina is a species of aquatic plant known by the common names spiny water nymph, spiny naiad and holly-leaved naiad. It is an extremely widespread species, reported across Europe, Asia, Africa, Australia, the Americas and many oceanic islands. It can be found in many types of freshwater and brackish aquatic habitat, including bodies of alkaline water.
Description
Najas marina is an annual producing a slender, branching stem up to 40 or 45 centimeters in maximum length. The evenly spaced leaves are up to 4 centimeters long, 1 to 3 millimeters wide, and edged in tiny sawlike teeth. The leaf has prickles along its midvein. Minute stalkless, green flowers occur in the leaf axils. The plant is dioecious, with male and female flower types occurring on separate individuals. In the British Isles it is possible that only female plants occur. It flowers in mid-summer.Varieties and subspecies
A long list of varietal and subspecific names have been proposed over the years. At present, only nine are widely accepted:- Najas marina subsp. arsenariensis L.Triest - Algeria
- Najas marina var. brachycarpa Trautv. - China and Kazakhstan
- Najas marina subsp. commersonii L.Triest - Madagascar, Mauritius, Réunion
- Najas marina var. grossidentata Rendle - Korea and Manchuria
- Najas marina var. intermedia Rendle - Spain, Sicily, Africa, the Middle East, China, Sri Lanka
- Najas marina var. marina
- Najas marina subsp. marina
- Najas marina subsp. sumatrana L.Triest - Sumatra
- Najas marina var. zollingeri Rendle - Bali