Growth Forms in the Florideophyciae

In my simple Model, the alga has an Apical Cell which produces a central, axial filament that consists of individual elongate cells. "Primary" Branches are produced periodically along the Central Filament.
This model is the same as the one above except that there are many more branches that form next to each other along the Central Filament. I will call these "Secondary" Branches. Cell fusions occur in the Rhodophyta. This can occur after the cells are otherwise mature. This makes the separate branches appear to be one structure.
In this model the Secondary Branches attain the same size as the Primary Branches. The cells in adjacent branches can fuse and produce a laminar sheet of photosynthetic cells.
The final product resembles a Fern Gametophyte which has an Apical Cell in its Apical Notch. This produces a flat 2-dimensional Thallus.
	The Freshwater species Caloglossa leprieurii bears a strong resemblance to the fern gametophyte above. However, they are not identical because the lateral cells in C. leprieurii are derived from branches & fuse after they are produced while the cells of the fern gametophyte are interconnected at their inception.
	*This is the tip of a species in the genus Apoglossum* (Rhodophyta). Note the Apical Cell and the central Primary Filament. The cells in the lamina are from branches that have fused.**
This is part of the Primary Filament of Pleonosporium sp. (Rhodophyta). It has branches that are produced at regular intervals. I am going to use my computer to suggest a way that this could lead to a flat thallus.
I have added some Branches.
I have added more branches and have made an alga with a Central Filament and closely spaced branches. If I continued this process, I could wind up with a Thallus like Apoglossum (above)
Link to Derek Keats discussion of thallus organization
Click the name below to go to his Coralline Algae Website of Derek W. Keats