Parenchymatous and Pseudoparenchymatous Algae
FIGURE 1.15 Pseudoparenchymatous thallus of Palmaria palmata.
These algae are mostly macroscopic with undifferentiated cells and originate from a meristem with
cell division in three dimensions. In the case of parenchymatous algae, cells of the primary filament divide in all directions and any essential filamentous structure is lost. This tissue organization is
found in
Ulva (Chlorophyta) and many of the brown algae. Pseudoparenchymatous
algae are made up of a loose or close aggregation of numerous, intertwined,
branched filaments that collectively form the thallus, held together by mucilages, especially in
red algae. Thallus construction is entirely based on a filamentous construction with little or no
internal cell differentiation.
Palmaria (Rhodophyta) (Figure 1.15) is a red alga with a complex
pseudoparenchymatous structure.
FIGURE 1.15 Pseudoparenchymatous thallus of Palmaria palmata.