Silvetia compressa deliquescens
Geographic Range 3
Silvetia compressa subsp. deliquescens is found only on islands including the Channel Islands and some near shore islands in Mexico, replacing the mainland species (Silvetia compressa) in the mid intertidal on these islands.
Morphology and Identifying Characteristics 3
Silvetia compressa deliquescens is a mid-intertidal seaweed with a distinctive "mop-head", bushy form. It is yellowish-brown to olive green in color. It produces several main axes from a discoid, conical holdfast, and branches dichotomously throughout the thallus. The dichotomies are typically uneven and about 3-5 cm apart. The ultimate dichotomies (receptacles) of the thallus are flattened and bumpy. The bumps on the receptacles are the conceptacles, where gametes are released.
S. compressa ssp. deliquescens is smaller and is very yellow compared to the mainland species, Silvetia compressa. S. compressa ssp. deliquescens also has somewhat narrower axes, smaller dichotomies/receptacles, and a bushier form.
Life History 4
Silvetia compressa deliquescens is a perennial seaweed. Unlike other brown algae groups, S. compressa deliquescens (order Fucales) does not undergo alternation of generations, but has a diplontic life cycle. It produces sperm and (usually) 2 non-motile eggs within the conceptacles (cavities on the receptacle). These gametes unite, forming a zygote, which then begins developing into the adult thallus after ~2 months. Individuals can be either monoecious or dioecious.
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.
Ecology 4
Silvetia compressa deliquescens forms a dense canopy in the middle intertidal zone. This canopy provides refuge for many algae and invertebrates that are sensitive to desiccation stress.
Sources and Credits
- (c) seavivs, some rights reserved (CC BY-NC), uploaded by seavivs
- (c) cppmarinebotany1, all rights reserved
- Adapted by intertidalecologist from a work by (c) cppmarinebotany1, some rights reserved (CC BY-SA)
- (c) cppmarinebotany1, some rights reserved (CC BY-SA)
More Info
iNat Map
| Common name | Algae, Brown Algae |
|---|---|
| Region | Channel Islands North, Channel Islands South |
