306 FRESH-WATER ALG^ OF THE UNITED STATES. 



Syn. Chthonoblmtm repens, Kg.; Microcoleus repens, Hass. ; 

 Vaginaria vulgaris. Gray ; V. chthonoplastes, Grev. ; Chtho- 

 noblastus Vaucheri, Kg. 



Plate CCY, figs. 16, 17, var. repens. 

 Plate CCIII, figs. 7, 8, 9, var. Vaucheri. 



MICROCOLEUS ANGUIFORMIS, Harv. 



Stratum thin, skin-like, aeraginons ; trichomes flexuous, 

 often twisted in dense fascicles ; articulations nearly twice 



/ */ 



as long as wide, sometimes indistinct ; often attenuated near 

 the apices, special sheath very delicate ; universal sheath 

 narrow, thin, colorless, ends open. 



Diameter of trichomes, 3.5-4; fascicles, 30-40 yw or more. 



Syn. Chthonoblastus anguiformis, Kg.; Ch. lacustris, Rab. ; Mic. 

 chthonoplastes, Thur. 

 Both affect moist earth, borders of pools and the like. 



Plate CCV, fig. 1, a peculiar coil from small pool, Atsion, 

 New Jersey. Plate CCIII, figs. 5-9, different conditions 

 which represent alike the present and the preceding species 

 (M. terrestris). When the trichomes measure 3.5-4.5 //, the 

 plant is recognized as of the present species, and when they 

 measure 5-6 //, it would be termed M. terrestris. They run 

 together, and are often not separable. 



MICROCOLEUS GRACILIS, Hass. 



Thallus membranaceous, skin-like, expanded, green, aeru- 

 ginous, or with age dark olive green, blackish. Trichomes 

 many included in a general sheath, which is usually wide, 

 yellow or colorless, articulations variable, one to three times 

 as long as wide. 



Kirchner suggests three varieties, viz: 



Var. SALINUS, Kg. 



Thallus thin, blackish green. 



Var. LYNGBYAI, Eab. 



Thallus bright aeruginous, often lamellose. 



Var. AERUGINEUS, Eab. 



Diameter of trichomes, 2.8-3/t; general sheath of fas- 

 cicles often 140 //. 



Syn. Microcoleus marinus, Harv.; Chthonoblastus salimis, Kg.; 

 OsciUatoria chtJionoplastes, Eng. Bot. 



Plate CCIII, figs. 10, 11, from specimens from swamps, 

 Dakota. 



