Monterey Bay Aquarium Research Institute
Marine Botany

Plocamium Reproductive Characteristics

The genus has multinucleate cells, displays pseudoparenchyma, has a tri-phasic life history with a carposporophyte growing on the gametophyte, and is diecious. Females produce spherical, protuberant cystocarps from a four-celled procarp, made up of a carpogonium, two carpogonial branch cells, and an auxiliary cell (which is also the supporting cell of the carpogonial branch and has two or more vegetative laterals attached to it). Of the three cells in the carpogonial branch (which has a trichogyne), two of them (all cells except the carpogonium) degenerate after fertilization. Inside the cystocarp, the gonimoblasts develop outward from the initial gonimoblast which results from the fused (through secondary pit connections) auxiliary cell and fertilized carpogonium. Most of the cells in the cystocarp become carpospores. The cystocarp does not have a carpostome. Males release spermatia from antheridia on the outside of terminal ramuli. Tetrasporophytes produce zonate tetraspores inside stichidia.

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