CONFERVOIDEsE 



279 



Hansgirg (Bot. Centralblatt, 1885) believes that the filamentous genera 

 placed in this genus are connected genetically with forms classed under 

 the Chaetophoraceae, Siphonocladaceae, and Ulvaceae. To this order 

 belong also Hormidium (Ktz.) and Schizogonium (Ktz.).. Wildeman 

 (Bull. Soc. Bot. Belg., 1886, p. 7) traces a genetic connection between 

 Ulothrix and Pleurococcus. 



LITERATURE. 



Cramer Vierteljahrschrift Nat. Gesell. Ziirich, 1870. 

 Cier.kowski Mel. biol. Bull. Acad. St. Petersbourg, 1876, p. 531. 

 Dodel-Port Pringsheim's Jahrb. wiss. Bot., 1876, p. 417; Bot. Zeit., 1876, p. 177. 

 Gay Bull. Soc. Bot. France, 1888, p. 65. 

 Hansgirg Flora, 1888, p. 259. 



ORDER 4. CHROOLEPIDE^E. 



This order, as constituted by Borzi, comprises a small group of 

 algae found on damp walls, the trunks of trees, and similar situations, 

 not unfrequently imbedded in the thallus of lichens, or constituting their 

 gonidial element. The thallus consists of a branched or unbranched 

 filament of cells, usually 

 somewhat rounded or mo- 

 niliform in outline, and is 

 distinguished by the mask- 

 ing of the colour of the 

 chlorophyll by a golden 

 yellow, orange, or red oily 

 pigment, soluble in alcohol 

 and imparting a strong 

 odour of violets. This pig- 

 ment, which occasionally 

 occurs also in other lowly 

 organised algae and proto- 

 phytes, has been examined 

 by Rostafinski, and found 

 to be a derivative of chlo- 

 rophyll to which he gives 

 the name chlororufin. 

 Microzoospores or zooga- 



. __. _, Bleischii Rbh. A, filament with 



ITieteS and megaZOOSpOrCS swollen cells in which the zoogametes are formed (game- 



, - .. tanges), g; , stages in the conjugation of the zoogametes 



are produced in gametanges ( x 33 o). (After wiiie.) 



or zoosporanges, which are 



indistinguishable from the vegetative cells except by their somewhat larger 



size, and which are either terminal or intercalary. Conjugation of the 



