Cymodoceaceae Family of Manatee Grasses

One Manatee Grass of the Cymodoceaceae Family can be found in this website:

Shoal Grass, Halodule wrightii. A representative member of the Cymodoceaceae Family of Manatee Grasses.

Phylogeny: Manatee Grasses of the Cymodoceaceae Family are in the phylum Tracheophyta. Tracheophytes, unlike Bryophytes, are vascular plants that have have tissues (phloem and xylem) that allow for the transport of water and nutrients within the plant via leaves, roots and stems. They have a cuticle (waxy layer to hold in water) and stomata (pores for gas exchange). Tracheophytes may either reproduce by seeds or spores. They are in the class Magnoliopsida, which are flowering plants that have branching leaf veins and flower parts in multiples of four or five. Other plants in this class include roses, oak trees and dandelions. The Cymodoceaceae Family is one of nine families in the order Alismatales. Alismatids grow in terrestrial, fresh water and marine environments. The Cymodoceaceae Family is fairly small, and is composed of six genera and seventeen species. The Cymodoceaceae Family was named after Cymodoce, a sea nymph of Greek mythology.

Habitat and Distribution:  Manatee Grasses are found growing on sand, mud, silt, or rocky substrates. They often grow in thick, carpet-like beds. Where water clarity allows for sufficient sunlight penetration, Manatee Grasses can grow to depths exceeding 30 m (100 feet). Most species are found in much shallower water, because they tend to grow in turbid in-shore water. They are found in the subtropical to tropical waters of the Indian, Pacific, and Atlantic Oceans.  One species from the Cymodoceaceae Family is found along Mexico’s east coast in the Carribean and Atlantic Oceans and one species is found along Mexico’s west coast in the Pacific Ocean.

Morphology:  Manatee Grasses are not true grasses, but are instead perennial flowering marine plants. These plants can vary significantly in appearance. They may live completely submerged, have floating leaves and flowers, or have leaves and flowers that emerge from the water.  The leaves are long and narrow and may be opposite or alternate along the stem. Some are wiry, others are made of air-filled tubes. The flowers are small and may be solitary or aggregated. They are anchored to the bottom substrate by rhizomes. Manatee Grasses can grow to at least 50 cm (20 inches) in length.

Reproduction:  Manatee Grasses are angiosperms (flowering plants) that produce flowers and seed containing fruits while entirely submerged in marine ecosystems. They can exist as separate male or female plants, or have both sexes on one plant. They may either reproduce by seeds or spores.

Ecosystem Roles:  Manatee Grasses are valuable indicators of a healthy ecosystem. They provide food and shelter to many species of shore birds, fish, sea turtles, and invertebrates. These plants often grow in large beds of numerous individual plants that are an important nursery for juvenile fish. Manatee Grasses also are critical for healthy coral reefs as they help to remove sediment from the water that might otherwise smother the coral polyps.