Resembling a dwarf Fucus, and even behaving like Fucus (if one were to
believe that algae can behave in specific manners at all), Pelvetiopsis
grows mostly atop of rocks in the upper intertidal zone. One way to
distinguish these two from each other, is to look for a midrib. Fucus has a
midrib and Pelvetiopsis lacks the midrib. Also, believe it or not, if you
squeeze the receptacles (swollen tips) of Fucus, an ooze will come out.
This ooze undoubtedly contains Fucus eggs which if you have
microscopic vision, you can see that the eggs are composed of 8, yes count them 8
functional eggs. Pelvetiopsis on the other foot, only has 1 functional egg