Stephanocystis setchellii
Cystoseira setchellii
Geographic Range 4
Stephanocystis setchellii is found subtidally at Shell Beach (San Luis Obispo County, CA), and from Redondo Beach, CA to San Diego, CA. It is also found on Catalina Island.
Morphology and Identifying Characteristics 4
Stephanocystis setchellii is a brown subtidal seaweed that is usually less than 1 meter tall. It has a bushy form with broad bipinnate branches. The receptacles of S. setchellii are similar to those of Stephanocystis osmundacea, in that they are a chain of well-defined spherical chambers resembling air-bladders. On occasion, solitary receptacles are present on the thallus, as well. The receptacles are found on the upper branches of the thallus, becoming sparser farther down the thallus.
Stephanocystis setchellii is much more fern-like and bushier than its congeners, S. osmundacea and S. dioica, and is also typically much shorter.
Life History 4
Stephanocystis setchellii is a dioecious perennial seaweed. Unlike other brown algae, S. setchellii (order Fucales) does not undergo alternation of generations, but has a diplontic life cycle. It produces sperm and (usually) 1 non-motile egg within the conceptacles (cavities on the receptacle). These gametes unite, forming a zygote, which then begins developing into the adult thallus after ~2 months.
It has more complex tissue than some other phaeophytes, in that it has medullary, cortex, and meristoderm (structural/epidermal) cells. It has trumpet hyphae in its medulla to facilitate transport of photosynthates to the apical meristem.
Sources and Credits
- (c) cppmarinebotany1, all rights reserved
- (c) Smithsonian Institution, National Museum of Natural History, Department of Botany, some rights reserved (CC BY-NC-SA), https://collections.nmnh.si.edu/services/media.php?env=botany&irn=10119344
- (c) Smithsonian Institution, National Museum of Natural History, Department of Botany, some rights reserved (CC BY-NC-SA), https://collections.nmnh.si.edu/services/media.php?env=botany&irn=10119346
- (c) cppmarinebotany1, some rights reserved (CC BY-SA)
