below, but mostly cylindrical in the branches, which are but slightly 

 reduced in diameter toward the apices. Walls either smooth or 

 externally tubercular. Cells in the main axis 11-30/x in diameter. 

 Gametangia globular, lateral on the branches, or terminal; 20-38ja 

 in diameter. Sporangia usually terminal on curved cells; about the 

 same size as the gametangia. 



Forming extensive velvety growths on flat surfaces of moist rocks, 

 cliffs, and tree trunks; in northern counties, especially along the 

 Lake Superior shore. Mich. 



Trentepohlia aurea var. polycarpa ( Nees & Mont. ) Hariot 



1889-1890, p. 374 

 A variety with especially roughened tubercular cell walls; game- 

 tangia up to 45/A in diameter, occurring in series. 

 Mich. 



Trentepohlia lolithus (L.) Wallroth 1833, p. 151 

 PI. 19, Figs. 4-8 

 Plants golden-red, forming a compact felt on moist rocks. Basal 

 filaments composed of fusiform or slightly swollen cells. Branches 

 possessing cylindrical cells and ending in bluntly rounded apices. 

 Cell walls roughened, often clearly lamellated. Sporangia globose; 

 terminal, or lateral on much curved or hooked stalks. Cells 14-35/a 

 in diameter, 24-50/i, long; sporangia 20-48//, in diameter. 



Rare; forming orange or golden-red, felt-like expansions on rocks 

 and logs in forested ravines. Mich., Wis. 



ORDER CLADOPHORALES 



In this order the plants are filamentous, usually branched, with 

 multinucleate cells. Some forms are permanently attached, but others 

 become free-floating and occur as tangled mats. In two genera 

 especially, Cladophora and Basicladia, there is a basal-distal differ- 

 entation with the branches gradually attenuated to bluntly rounded 

 apical cells. There are no setae or hair-like extensions of the 

 branches. The chloroplast form has two primary expressions. In 

 some it is a parietal network or reticulum covering most of the cell 

 wall, or there may be many disc-like chloroplasts, also parietal. 

 Each cell contains many pyrenoids. Starch grains frequently are so 

 abundant as to obscure the form of the chloroplasts. In many 

 forms the walls are thick, sometimes lamellate, always without an 

 external mucilaginous layer. This accounts for the fact that members 

 of this order are often heavily epiphytized by diatoms and other 

 algae. Most species are macroscopic, attaining a length of 10 cm. 

 or more, and are coarse and wiry. 



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