1885.] 



MiOROSCOriCAL JOURNAL. 



173 



parts. Zoospores egg-shape,with four 

 cijia and a red pigment spot. 



[This genus is endophytic in the 

 gelatinous envelopes of such algie as 

 Tetraspora, C/i(etop/iora, Batra- 

 chospcr/n/an, etc.* growing along 

 and winding about the filaments of the 

 latter.] 



6i . Genus Draparnaldia Agardh. 



Main filament larger than the 

 branches, colorless, or with less color 

 than the latter, bearing bright green 

 clusters of smaller branches diflering 

 also in form from the main stem ; 

 terminal cells of branches end in col- 

 orless hairs. All the cells of the 

 branches may form resting -spores. 

 The entire plants, enveloped in slimy 

 mucilage, forming soft, shapeless 

 masses. 



[The very pronounced difference 

 between the main stem and the 

 branches of this plant enable the ge- 

 nus to be recognized at a glance. 

 Usually the coloring matter of the 

 cells of the main stem is arranged in 

 a more or less broad band across the 

 cells. In at least one species it has 

 been obsei"\'ed that the fascicles of 

 branches (the main stem of the 

 branches being likewise larger than 

 the others) may grow into new 

 plants, sometimes sending out rhi- 

 zoids from the basal cell. This is a 

 very beautiful alga, not uncommon.] 



62. Genus St/geocIoniumYJXt/An^. 

 Principal stem not distinct in size 



or form from the branches, with green 

 contents, or colorless ; the ultimate 

 branches not aggregated into distinct 

 fascicles. Otherwise like Drapar- 

 naldia. Resting-spores produced in 

 the last branches. 



[The terminal cells of some of the 

 species end in long, colorless hairs. 

 The green contents are usually ar* 

 ranged in transverse bands across the 

 cells. The formation of zoospores 

 and their escape from the ruptured 

 cells can frequently be observed in 

 this genus.] 



63. Genus CJuvtophora Schrank. 

 Stem and branches alike, radiately 



arranged, or forming layers of definite 



form. The entire plant surrounded 

 withr a firm gelatinous envelope, 

 sometimes very hard. The cells of 

 the ultimate branches form chains of 

 resting-spores. 



[These plants are often found at- 

 tached to submerged leaves, twigs or 

 other plants, in the form of minute, 

 solid particles of transparent jelly of 

 a dense green color. The chlorophyll 

 is usually arranged in transverse 

 bands, as in Draparnaldia and 

 Stigeoclonium. The terminal cells 

 are often attenuated, and may appear 

 quite empty. Zoospores may fre- 

 quently be seen forming in the cells. 



The more or less hard, or coriace- 

 ous, hyaline envelope which surrounds 

 the filaments is not characteristic of 

 this genus, as it is found also among 

 the NostocacccE. The green color of 

 the filaments and the manner of 

 branching prevents any liability to 

 error in distinguishingbetween them.] 

 (3. Filaments without gelatinous 

 sheaths ; no rhizoids. 

 Synopsis of Genera. 



Articulated, branching filaments, 

 spreading irregularly over surfaces, 

 cells with long bristles. 



Aphanoch<^te.^ 64. 



Filaments upright, branched, ter- 

 minal cell obtuse. 



Alicrothamnion, 65. 



64. (je.w\x% Aphanochcete K. Braun. 

 Filaments prostrate, creeping, 



growing closely attached to a surface, 

 often on larger filamentous algie, 

 branching and spreading irregularly. 

 Some of the cells bear long bristles 

 either at their apex or on the back. 



65 . Genus Microthaninion Niigeli . 

 Filaments articulate, upright, 



straight, dichotomously or trichoto- 

 mously branched, sometimes very 

 much branched ; terminal cell ob- 

 tuse, without bristle, afterward swol- 

 len, forming a sporangium. Distin- 

 guished by the peculiar method of 

 branching — the lower of two cells 

 sends out a lateral growth in which 

 the dividing wall is formed, not at 

 the point where the branch origi- 

 nates but a short distance above it. 



