Bryopsidales is an order of

green algae The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants ( Embryophytes) have emerged deep in the Charophyte alga ...

, in the class

Ulvophyceae The Ulvophyceae or ulvophytes are a class of green algae, distinguished mainly on the basis of ultrastructural morphology, life cycle and molecular phylogenetic data.Graham LE, Graham JM, Wilcox LW (2009) ''Algae''. 2nd Edition. Benjamin Cummin ...

Characteristics

The

thallus Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms wer ...

is filamentous and much branched and may be packed into a mass. It is

coenocytic A coenocyte () is a multinucleate cell which can result from multiple nuclear divisions without their accompanying cytokinesis, in contrast to a syncytium, which results from cellular aggregation followed by dissolution of the cell membranes ins ...

, having multi-nucleate cells consisting of

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. T ...

contained within a cylindrical

cell wall A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mec ...

. There are no septae and the many discoid chloroplasts, nuclei and other organelles are free to move through the organism. The whole organism may consist of a single cell and in the genus '' Caulerpa'' this may be several metres across. In the genus '' Halimeda'', whole seabed meadows may consist of an individual, single-celled organism connected by filamentous threads running through the substrate.

Reproduction

Propagation is normally vegetative from small fragments which grow into new individuals. Under certain conditions sexual reproduction occurs in a process called holocarpy. Almost all of the cytoplasm in the

is converted into biflagellate

gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...

s, which are discharged into the sea through papillae. After fertilisation, the

zygote A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism. In multicel ...

becomes a

protonema A protonema (plural: protonemata) is a thread-like chain of cells that forms the earliest stage of development of the gametophyte (the haploid phase) in the life cycle of mosses. When a moss first grows from a spore, it starts as a ''germ tube'', ...

and this in turn develops into a new thallus.Overview of the Genus ''Caulerpa''
Proceedings of the International ''Caulerpa taxifolia'' Conference, 2002.

References

{{Taxonbar, from=Q6452523 Chlorophyta orders