174 



THE AMERICAN MONTHLY 



[September, 



Contents eftnsed, with starch (gran- 

 ules. 



[The plants of this genus are quite 

 small, and appear to have at times 

 a gelatinous investment. The cells 

 are sometimes distinctly swollen or 

 turgid.] 



b. Cladophore.e. Sub-group 3. 

 Synopsis of Genera. 



Aerial branching filaments ; con- 

 tents reddish or bright red. 



Chroolepus^ 66. 



Filaments branching; cells ro- 

 bust, much longer than the diameter ; 

 branches becoming smaller than the 

 main stem. C/adop/wra, 67. 



Filaments branching once or twice ; 

 cells short, often torulose. 



Go)igrosiray 6^. 



66. Genus Chroolepus Agardh. 

 Filaments irregularly branched, 



often so felted together that it is dif- 

 ficult to recognize the branching. 

 Cells with red or reddish brown con- 

 tents, sometimes turning green after 

 death. Zoospores usually as many 

 as 32, reddish brown, with two cilia. 

 No rhizoids ; resting-spores unknown. 

 Aerial algae, often with a strong odor 

 of violets. 



[The color of the filaments is often 

 distinctly yellow or orange. The cell- 

 walls are thick and firm. The alga^ 

 are found on rocks where water 

 trickles down, as a somewhat thick, 

 leathery growth.] 



67. Genus Cladophora Kiitzing. 

 Filaments many times branched ; 



the last branches much thinner than 

 the primary. Cells robust, usually 

 several times longer than thick, with 

 green contents and usually numerous 

 starch granules ; the first cell with a 

 rhizoid. 



Zoospores, with 2-4 cilia, formed in 

 great number in a mother-cell. Rest- 

 ing-spores not known. 



[The cell-walls are very thick, often 

 lamellose. The cells are frequently 

 very long in proportion to their diam- 

 eter. The green contents seem to be 

 quite uniformly distributed over the 

 inner wall of the cells. 



This genus has numerous repre- 

 sentatives among' the marine algf^e. 



Chieto))io)pJia (=59) resembles this 

 genus so closely that it is only to be 

 distinguished by the absence of 

 branches.] 



68. Genus Gon£'rosira Ktitzing. 



Filaments usually dichotomously 

 or simply bi'anched, branches as thick 

 as the principal stem ; cells with thick 

 walls, with green contents. The 

 lower cell with a filamentous rhizoid. 

 Resting-spores. Living in water or 

 aerial. 



[The filaments are not repeatedly 

 branched as in CladopJwra^ and the 

 cells are quite short, either equal in 

 length to their diameter, or twice as 

 long, often constricted at each end so 

 as to form torulose filaments. 



Rabenhorst describes two genera 

 under his family Gongrosireae which 

 we have not regarded as sufficiently 

 distinct from Gongrosira to be main- 

 tained as independent genera. Their 

 characters are brieflv given as fol- 

 lows : — 



Geww&Pilinia Kiitzing. Erect, ar- 

 ticulate filaments, simply or sparsely 

 branched, attached, in a crustaceous, 

 spongy stratum, of an olive color. 

 Propagation unknown. 



Genus Chlorotylinm Kiitzing. 

 Filaments dichotomously branched, 

 erect, parallel, in thin, pulverulent 

 stratum, not laterally connected, not 

 vaginate. Elongated hyaline cells in- 

 terspersed in the filaments between 

 short, tumid cells with colored con- 

 tents. Zoospores 4-16 in a single 

 cell.] 



[7^0 be continued.^ 



O 



• — The microscopical exhibit of the U. 

 S. Department of Agriculture at the New 

 Orleans exposition, prepared by Dr. 

 Thomas Taylor, was made up in great 

 part of water-color illustrations of fungi. 

 Of these there were 800 plates, represent- 

 ing nearly 700 species. The remaining 

 exhibits showed the results of experiments 

 on butter, fats, and fibres of various kinds 

 treated with reagents. A catalogue of the 

 exhibit is published and can be obtained 

 by application. 



