COLEOCHAETE. 63 



Class II. CHLOROPHYCE^S. 



Plants normally with cell contents of a chlorophyl-green color, 

 aquatic or serial, one, two, or many celled, either single or asso- 

 ciated in families ; branched or simple. Cell contents sometimes 

 change to crimson, flesh-color or yellow-brown, often with a cen- 

 tral or lateral nucleus. Vegetation by cell division. Fecunda- 

 tion often sexual. Propagation either by oospores or zygospores 

 or gonidia. 



Order II CONFER VOIDED. 



Filiform algse, simple or branched ; vegetation terminal, un- 

 limited ; sometimes united laterally ; cell contents chlorophyl- 

 green. Propagation in some genera is sexual, there being female 

 cells (oogoiiia) which contain one or sometimes more oospores, 

 and male cells (antheridia) in which spermatozoids are devel- 

 oped. In some cases copulation of zoogonidia (swarming spores ) 

 has been observed (Cladophora and Ulothrix); the exact mode of 

 propagation of other genera is not satisfactorily determined. 



Family V.COLEOCHAETACE^E. 



Small, bright green water plants either sexual or asexual. 

 The oogonium is a round cell resting 011 the end of a slender 

 'neck, the continuation of an end cell of the frond. The an- 

 theridia, 2 or 3, are formed on a neighboring cell or on a separate 

 frond, and emit the spermatozoids which by means of two cilise 

 reach the oogonium and fertilize the oospore, which corticates 

 and becomes a resting or winter spore, developing the following 

 Spring. 



Asexual propagation takes place by zoogonidia which may be 

 developed in any of the cells ; they are provided with two cilise, 

 in appearance like the spermatozoids, but considerably larger. 







Genus 9, COLEOCHAETE, Breb. 



Filaments articulated, branched, either conjoined into a little 



cumulated mass or parenchymatously concreted into a plain sub- 

 5 



