An Introduction to the Study of Seaweeds
by George Robert Milne Murray (9781458811899)

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: SUB-CLASS I textit{PHjEOPHYCEjE With the exception of some of the species of textit{Lithoderma and the genus textit{Pleurocladia, represented only by a minute form of doubtful affinity discovered by Alexander Braun in the Tegeler See near Berlin, all the textit{Phceophycece, or textit{Melanophycece as they are otherwise called, are seaweeds. They agree in the fact that all their motile reproductive cells, zoospores, antherozoids, and gametes are provided with two lateral cilia, one pointed forwards and the other backwards in motion; in the fertilisation of their oospheres and the conjugation of gametes outside the parent plant, and the direct germination of the zygote which is the product of this union; in the possession of brown chromatophores tinged with phycophaeine and phycoxanthine (the phyco- phaeine being soluble in water and the phycoxanthine in alcohol, the compound pigment being termed phaeophyll); and in having mostly but one nucleus in the vegetative cells. The vegetative body of the plants coming under this sub-class is of great diversity, including the most highly organised of all seaweeds, of giant dimensions andgreat external differentiation of form and considerable internal differentiation of tissue, as well as others consisting of a mere row or plate of similar cells. The sub-class may be regarded as a fairly natural assemblage of orders easily to be distinguished from the other sub-classes, though it includes such diverse types as (1) the textit{Fucacece, of which the unciliated oospheres, many thousand times greater than the antherozoids, are produced like the latter in definite conceptacles, from which they are extruded; (2) the textit{Cutleriacece, possessing non-sexual zoospores, and ciliated oospheres (or 5 gametes) many times larger than the anthero...

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