Range: Vancouver - Baja Calif. depth: 6-18 (38) m.
Table of Contents
The Sea Grape
Commonly known as "sea grapes," Botryocladia (botryo=grape,
cladia=branches) pseudodichotoma is an abundant member of the RHODOPHYTA
(red algae). The following phylogeny consists of links to list of common
characteristics which justify Botryocladia's inclusion:
- thallus is 10-30 cm. tall
- elongate, pyriform (pear-shaped), sacchate (sack-like) branches
- sacchate branches are 4-7 cm long and 6-25 mm in diameter
- branches contain a colorless, acidic, polysaccharide and protein
mucilage which makes them bouyant and therefore better able to
compete for light
- 3 cell layers
- pigmented cortical cells
- unpigmented medium sized gelatinous cells
- unpigmented large gelatinous medullar cells (& specialized
gland cells cluster in groups of 10-20 on the inward facing surface
of medullar cells which in pseudodichotoma are noticeably
smaller than its neighbors. It is easy to view secretory cells under
a microscope by making cross-sections with a razorblade.
with all Florideophyceae, B.pseudodichotoma has a tri-phasic life
cells of the diploid tetrasporophyte undergo meiosis to create cruciate
tetraspores (3.88 million/day). Each of the 4 spores can grow into
a haploid gametophyte (male or female).
mature male gametophyte emits spermatia which fertilize cells on
the female gametophyte. Where fertilization has succeeded, a diploid
carposporophyte grows on the female gametophyte.
carposporophyte has a pore opening to the outside through which it
releases diploid carpospores. These carpospores settle and grow into