Gracilaria salicornia (C. Agardh) E.Y. Dawson

Gracilaria salicornia (C. Agardh) E.Y. Dawson




Sphaerococcus salicornia C. Agardh, Corallopsis salicornia (C. Agardh) Grev., Gracilaria minor (Sond.) Durair.

Vernacular Names

Indonesia Agar-agar, bulung buku, sango sango (Sulawesi).
Philippines Susueldot bay bay (La Union Province, for G. crassa), canot-canot, lagot.
Thailand Sarai kaw.
Vietnam Rau cau chung vit (for G. crassa).

Geographical Distributions

Gracilaria salicornia is found along most tropical coasts of the Indian and Pacific Oceans. In Southeast Asia, it occurs on the coasts of all countries.


G. salicornia can grow up to 15 cm tall. It is greenish-purplish to orange. All axes, branches and branchlets are with more or less distinct claviform articulations. This plant is with or without main axes, regularly or irregularly branched and forms tight entangled masses or low prostrate caespitose clumps.

The fronds are cylindrical, brittle and fleshy, cartilaginous and succulent when fresh. The branching is irregular to dichotomous, trichotomous, tetratomous and divaricate. The branches are blunt, truncated or with a somewhat acute at the apex.

The thalli is with large medullary cells, measuring 250-600(-720) µm in diametre in transverse section and with 2-15 µm thick of the cell walls. Transition of cells is cortex, measuring 10-15 µm x 20-30 µm in diametre, gradual or abrupt, with frequent roundish gland cells and measuring 30-35 µm in diametre.

The cortex cells are irregularly shaped, oblong, ovate or rounded and in 2-3 layers. Tetrasporangial and gametophytic plants are similar in size and branching pattern while segments in tetrasporophytes are often slightly larger. Tetrasporangia is scattered over the surface of thalli, numerous, cruciately divided, spherical to oblong and measuring 30-50 µm in diametre. Spermatangia cover the entire of the inner surface of deep pot-shaped conceptacle and measuring 26-50 µm x 85 µm in longitudinal section.

The cystocarps are nearly spherical, prominently protruding, usually with a distinct beak, constricted at the base or not, measuring 1-2 mm in diametre and irregularly disposed on the branches. The gonimoblast is with large thin-walled central cells which are connected to the pericarp by many absorbing filaments. The pericarp is 180-265 µm thick and with 2 layers of tissue. The elongated cells are in the outer layers and the brick-like cells in the inner layers. The carpospore is spherical, measuring 23-30 µm in diametre and produced in chains.

Ecology / Cultivation

G. salicornia grows on various substrates: rocks, gravel, shells and mangrove roots. It is usually found in protected portions of reef flats away from the impact of wave action, or in waters exposed to moderate to strong water movement, attached to small rocks or pieces of dead coral or shells, or on sandy-rocky substrate. Occasionally, it is also found in shallow pools in intertidal terrigenous mudflats and between sea grasses. Temperatures exceeding 30°C are lethal to G. salicornia.

Line Drawing / Photograph



  1. Plant Resources of South-East Asia No. 15(1): Cryptogams: Algae.