Polysiphonia sentence example
- When the new cells grow no further, but constitute a palisading round the central cell covering its whole length, the condition is reached which characterizes the species of Polysiphonia, the " siphons " of which may be regarded as one-celled branches.
- Thus in Lemaneaceae asexual spores are unknown; in Batracho-spermum, Bonnemaisonia and Polysiphonia byssoides both kinds of sexual cells appear on the same plant; and in some cases the asexual cells may occur in conjunction with either the male or female sexual cells.
- In Polysiphonia they cover the joints of the so-called leaves; in Chondria they arise on flattened disks; in the more massive forms they arise in patches on the ordinary surface; in a few cases (Gracilaria, Corallina, Galaxaura) they line the walls of conceptacle-like depressions.
- Polysiphonia sp., transverse section through a branch, and at spores arising from fertilized carpogonium.
- In answer to this question a recent writer, Yamanouchi, states in a preliminary communication that he has found that in Polysiphonia violacea the germinating carpospores exhibit forty chromosomes, and the germinating tetraspores twenty chromosomes.Advertisement
- Algae of more delicate texture than either Fucaceae or Laminariaceae also occur in the region exposed by the ebb of the tide, but these secure their exemption from desiccation either by retaining water in their meshes by capillary attraction, as in the case of Pilayella, or by growing among the tangles of the larger Fucaceae, as in the case of Polysiphonia fastigiate, or by growing in dense masses on rocks, as in the case of Laurencia pinnatifida.
- Cladophora and Bryopsis among monosiphonous forms, Chara, Polysiphonia, Ceramium and Cystoseira among larger algae, are illustrations of this.