PALMELLATEE, a family or group of Algce, of the order or sub-order Conferracem In organization, they are among the lowest of plants; they are, however, universally regarded as vegetable, and do not, like the Diatornacete, occupy a somewhat doubtful position between the animal and vegetable kingdoms. The pahnellacere all grow on damp surfaces, but some under the influence of fresh water, and some of salt. Some appear es a mere powdery layer, the granules of which have little adherence to each other, as red snow (q.v.); some of them assume the form of a slimy film or gelatinous mass, as gory dew (q.v.); and some are more firm and membranous, so as to have something of the character of a frond. The pahnellacem bear so great a resemblance to the early stages of plants higher in organization, that doubts are entertained of their right to a distinct place in the botanical system, particularly as their mode of reproduction is not yet well understood. Conjugation has been observed in some of them. They propa
gate with great rapidity by gemination, or something like it, some of them sending forth tubular filaments from their cells, the extremities of which dilate into new cells, after which the connecting tube closes, aad ceases to exist; whilst iu others the multiplication of cells takes place by division or segmentation (see MosAn), and the young plants exhibit remarkable powers of motion for .a short time, like zoospores, being furnished with vibratile cilia, by which their motion is' produced. Ere long, however, their motion ceases, and the process of segmentation is ready to begin anew. The motile organs and powers of some of the pahnellacew,.in the earlier part of their existence, have led to their being mistaken for animalcules.