Gracilaria

Class: Rhodophyceae

Order: Graclariales

Family: Gracilariaceae

Genus: Gracilaria

Gracilaria is common marine red algae found growing attached to the sub-stratum such as rocks by a basal cushion disc, (lithophytes). It has large dichotomously branched thallus also called fronds. It is composed of closely compacted vertical thread like fronds which are which are dark red or pink branches reaching up to 50cm in height.

The matured thallus shows little anatomical difference and T.S of the thallus shows three zones. They are peripheral layer of cell, cortex and medulla. The peripheral layer of cell is small uni or multi nucleated, some of them producing unicellular hairs. Inner to the peripheral layer is the cortex made up of many small cells having ribbon shaped chromatophores. The inner core of the thallus is medulla which contains large iso- diametric cells. The fronds are monosithonous and have a gelatinous envelope on the surface.

Economic importance

Gracilaria is extensively used for extraction of polysaccahrides, Agar. Used as a solidifying agent in nutrient media in microbiology labs.

Posted in: Microbiology