with individual gelatinous sheaths and embedded in a common 

 gelatinous matrix; with dark red, stellate chromatophore and small, 

 excentric nucleus. Reproduction by cell division. Forming blood-red 

 film on moist soil and walls, especially in greenhouses. 



Porphyridium cruentum Naegeli 1849, p. 139 



PI. 136, Fig. 6 



Characters as described for the genus. Size of cells variable: 

 5-9/x, 7-12/x, or up to 24/^. 



On soil in greenhouse. University of Wisconsin, Madison. 



SUBCLASS FLORIDEAE 



In this advanced group of the red algae the thallus has a multi- 

 plicity of expressions, ranging from slightly branched filaments to 

 complex plants of macroscopic size, involving complexes of fila- 

 ments which may be differentiated to form tissues. Growth in all 

 these forms occurs by the activity of one or more meristematic 

 apical cells. 



The sex organs, especially the female, are characteristic of the 

 group. The carpogonium has a definite neck-like extension, the 

 trichogyne, the shape of which varies in different genera and species 

 and is, therefore, of taxonomic value. See Smith (1933, 1938) and 

 Taylor (1937) for a description of morphological characteristics, 

 methods of reproduction, and outlines of life histories. 



ORDER NEMALIONALES 



There are four fresh-water families in this order, of which three 

 have representatives in the \^^isconsin collections. The fourth family, 

 Thoreaceae, undoubtedly is present in the plant Thorea ramosissima 

 Bory, but as far as known this species has not been reported from 

 the region. Sexual reproduction involves specialized female sex or- 

 gans (carpogonia), and antheridia which develop non-motile sper- 

 matia. In addition to gametangia, the sexual plant may produce 

 non-motile monospores cut off from the tips of branches, especially 

 in juvenile stages of development. 



FAMILY CHANTRANSIACEAE 



In this family the thallus is a filament which has repeated alter- 

 nate branching and is without a conspicuous central axis. 



AUDOUINELLA Bory 1823, p. 340 

 Thallus consisting of sparingly branched filaments of cylindrical 



[564] 



