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Siphonocladus tropicus showing segregative cell division. Siphonocladus is a small genus of green algae in the family Siphonocladaceae. [1] [2] The algal body is composed of long, club-shaped cells that divide by segregative cell division, followed by the formation of branches that break through the mother cell.
The primary thallus is composed of small, overlapping scales, while the secondary thallus (which supports the lichen's fruiting structures) is fruticose in appearance. [21] These secondary thalli, which are known as podetia , can be branched, spike-like or cup-shaped. [ 6 ]
A kelp, for example, may have its thallus divided into three regions. The parts of a kelp thallus include the holdfast (anchor), stipe (supports the blades) and the blades (for photosynthesis). [2] The thallus of a fungus is usually called a mycelium. The term thallus is also commonly used to refer to the vegetative body of a lichen.
Caulerpa is coenocytic, meaning it has a multinucleate thallus organization. It is also siphonous, meaning unlike other algae, the thallus and the nuclei are not separated by cell walls. They are instead one long mass of protoplasm surrounded by a single cell wall. [12]
In most coralline algae, a cluster of reproductive cells forms in the middle layer of the alga, and is engulfed by the surrounding tissue, which grows up and over the reproductive cells to form a roof and a uniporate conceptacle.
Charophyceae is a class of charophyte green algae. AlgaeBase places it in division Charophyta. [1] Extant (living) species are placed in a single order Charales, [2] commonly known as "stoneworts" and "brittleworts". Fossil members of the class may be placed in separate orders, e.g. Sycidiales and Trochiliscales. [1]
Desmarestiales is an order in the brown algae (Phaeophyceae). Members of this order have terete or ligulate (flat) pinnately branched thalli attached by discoid holdfasts.They have a sporophytic thallus usually aggregated to form a pseudo-parenchyma. [1]
Normally the photobiont occupies an extensive layer covering much of the thallus, but in tripartite lichens, the cyanobacterium component may be enclosed in pustule-like outgrowths of the main thallus called cephalodia, which can take many forms. These structures represent specialised compartments within what is now understood to be a complex ...