Marine Botany

Codium setchellii

Reproduction and Life History

Reproductive Structures

Specialized utricles within Codium produce the gametes. The gametangia appear as separate branches from the other utricles comprising the alga's internal structure. These transparent structures have dark, globular tips.


Figure 1: Schematic of the utricles of C. setchellii showing reproductive gametangia (After Scagel 1967)
(After Scagel 1967 and personal observations)

None of the specimens collected during winter 2005 were obviously reproductive. Various individuals were observed with enlarged utricles, that do appear to be gametangia, but are likely not fully developed. Records from Gardner (1919) show that C. setchellii is usually reproductive in the winter months, thus the presence of reproductive individuals would be expected.


Figure 2: Suspected gametangia of C. setchellii

Reproduction

The reproduction of C. setchellii has been inferred from the published data for the congeneric C. fragile, as the reproductive cycle of C. setchellii has yet to be fully investigated. The gametangia form separate from the utricles of the alga. These release anisogametes, typically with larger female gametes (anisogamy). Both male and female gametes are biflagellated, with symmetrical flagella. The tips of the gametangia become ripe with gametes seasonally and eject bursts of the gametes. Gardner (1919) noted fertile C. setchellii females in the winter months.

 

Life History

The life cycle of Codium setchellii is presently uninvestigated in the scientific literature. Most believe the life history is similar to that of the congeneric C. fragile (Bold and Wynne 1978). This species has a diplontic life cycle, meaning the alga is always diploid (containing two copies of the genetic information, much like humans). The diploid alga forms reproductive gametangia, where the gametes develop. These burst seasonally and release gametes, which fuse and the zygotes settle onto a substrate and develop into a new diploid alga. The alga is presumed to be dioecious, having separate male and female individuals. This life history is summarized below in figure 3.

Figure. 3: Presumed diplontic life history for Codium setchellii

Choose one of the following links to learn more about Codium setchellii:

|Taxonomy | Distribution | Habitat | Structure & Morphology | Cellular Structure |

| Reproduction & Life Cycle | Ecology | Epiphytes | References |

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© 2005 Raúl Nava.
Text and images freely available for personal, educational use (please credit).
Please e-mail me (rnava@stanfordalumni.org) for any other use (including publication or commercial use).

 

Last updated: Mar. 20, 2005