02 SIPHONED. 



out distinct differentiation in stem- or leaf-structures, sometimes 

 (e.g. Halimeda) it is very much incrusted with lime. In the 

 early stages it is unicellular (later, often multicellular), very 

 much branched, with the branches, at any rate partly, so united 

 or grown in amongst one another (Fig. 60) that an apparently 

 pai-enchymatous cellular body is formed. Akinetes or aplanospores 

 are wanting; zoospores (or 

 gametes ?) may be developed in 

 some species, however, in special 

 swollen sporangia. Fertilisation 

 similar to that in Bryopsis occurs 

 perhaps in Codium. They are 

 rill salt water forms. 



Order 8. Valoniaceae. The thal- 

 lus is generally multicellular, without 

 differentation into stem- or leaf-struc- 

 tures, but the cells are sometimes 

 united together and form a leaf-like 

 reticulate expansion (e.g. Anadyomene). 

 Zoospores are known in some, and 

 they are then formed directly in the 

 vegetative cells. In others (e.g. 

 Valonia), a mass of protoplasm, which 

 maybe separated through the damag- 

 ing of a cell, can surround itself with 



FIG. 59. Cnulcrpa, prolifera (natural size). 



a cell-wall, and grow into a new plant. No other modes of reproduction are 

 known. The most important genera are : Valonia, Siphonocladus, Chamadoris, 

 Strucea, Microtiictyon, Anadyomene. They are all salt water forms. 



As already pointed out, the Valoniaceer occupy a somewhat central position 

 among the Siphoneze, and present points of similarity and contrast with the 

 liotrydiacfa; and the Bryopsidacetc through Valonia, with the Dasycladaceee 

 through C)iama>doris, and also with the Cladophoracete through Siphonocladus, 

 and Slruvea. 



