Rhodophyceae sentence example
The algal fungi, Phycomycetes, are obviously derived from the Green Algae, while the remaining Fungi, the Eumycetes, appear to have sprung from the same stock as the Rhodophyceae.
None of the existing Red Seaweeds (Rhodophyceae) has a unicellular body.
Many of the lower forms of Brown Seaweeds (Phoeophyceae) have a thallus consisting of simple or branched cell threads, as in the green and red forms. The lateral union of the branches to form a solid thallus is not, however, so common, nor is it carried to so high a pitch of elaboration as in the Rhodophyceae.
In addition to the cell types described, it is a very common occurrence in these bulky forms for rhizoid-like branches of the cells to grow out, mostly from the cells at the periphery of the medulla, and grow down between the cells, strengthening the whole tissue, as in the Rhodophyceae.
Unknown in Cyanophyceae and Phoeophyceae, known only in Bangiaceae and Nemalion among Rhodophyceae, they are of frequent occurrence among Chlorophyceae, excepting Characeae.Advertisement
Rhodophyceae are mostly marine, but not exclusively so.
Most of the larger species of marine Rhodophyceae are attached by means of a disc to rocks, stones or shells.
Many are epiphytic on other algae, more especially the larger Phaeophyceae and Rhodophyceae.
No unicellular Rhodophyceae are known, although a flagellate organism, Rhodomonas, has recently been described as possessed of the same red colouring matter.
Vegetative multiplication occurs only sparingly in Rhodophyceae.Advertisement
The male cell is a spermatium, but the female cell bears no such receptive trichogyne as occurs in other Rhodophyceae.
Finally, while Chlorophyceae and Phaeophyceae exhibit important affinities, the Rhodophyceae are so distinct that the term " algae " cannot be made to include them, except when used in its widest sense.
Turn ing first to the Rhodophyceae, both on account of the high place which they occupy among algae and also the remarkable uniformity in their reproductive processes, it is clear that, as is the case among Archegoniatae, the product of the sexual act never germinates directly into a plant which gives rise to the sexual organs.
Even among Bangiaceae the carpospores arise from the fertilized cell by division, while in all other Rhodophyceae the oospore, as it may be called, gives rise to a filamentous structure, varying greatly in its dimensions, epiphytic, and to a large extent parasitic upon the egg-bearing parent plant, and in the end giving rise to carpospores in the terminal cells of certain branches.
The elaborate provision for the conduct of water from part to part which has played so important its allies, nor is it known in the whole of the Phaeophyceae and Rhodophyceae.Advertisement
The presence of phycocyanin, phyco a role in the morphological development of land plants is entirely wanting in algae, such conducting tissues as do exist in the larger Phaeophyceae and Rhodophyceae serving rather for the convection of elaborated organic substance, and being thus comparable with the phloem of the higher plants.
In the case of marine algae, the hosts are chiefly the larger Phaeophyceae and Rhodophyceae.
Thus simple forms included in the Heteroconteae, Chlorophyceae and Phaeophyceae show an obvious connection with the Flagellatae; the Peridineae may be regarded as a further developed branch; the Conjugatae and Diatomaceae cannot be directly connected; the origin of the Rhodophyceae is also obscure; while the Characeae are an advanced and isolated group (see ALGAE).
The algal fungi, Phycomycetes, are obviously derived from the Green Algae, while the remaining Fungi, the Eumycetes, appear to have sprung from the same stock as the Rhodophyceae (see FUNGI).