Shaving brush alga
Penicillus capitatus
Lamarck, 1813
Description:
The plants have a long stalk, up to 10 cm, and an oblong to spherical 'brush' of filaments of 3 cm. The plants are substantial calcified. The filaments are slender, but because of the calcification rather tough. Slight magnification reveals their repeated dichotomous branching. The stalks appear spongy under magnification. They are slightly constricted at their base, where the bulbous mass of rhizoids arises. The color of the plants is light green.
The plant is coenocytic.
Habitat:
Common in shallow, warm bays and lagoons, where it may form large colonies or be mixed with sea grasses.
Distribution:
South Florida, Bahamas and Caribbean.
Remarks:
The bristle ball brush, Penicillus dumetosus , is similar to P. capitatus , but the stalk is shorter and the head larger and looser. It is not so heavily calcified.
The pinecone alga, Rhipocephalus phoenix , resembles the species of Penicillus , but the filaments of the head are not separate and loose but are fused into radially arranged platelets. It is somewhat calcified, dull green and attains a height of about 7-12 cm.