THE FLORA OF NEBRASKA. :,1 



Cells yellowish-green, of ten orange yellow, sometimes a deep bl i-red; cell 



membrane rather thick, colorless; diameter of cells variable, 5 12 u, 



A conservatory variety, found on flower pots and on the walls and floors of 

 greenhouses. The blood-rod form so common in damp places has long 

 been known as Porphyridium omentum Naeo. It appears, however, to i»- 

 only an old condition or abnormal form of the above variety. PL I V .. 

 Fig. 11 c. 



2. TETBASPOBA Link in Schrad. Journ. II., 7, 9. 1809. 



Thallus gelatinous or membranaceous, at flrsi sac-like, then explanate; cells 

 globose or somewhat angular, scattered or arranged in families of 1 ot 

 rarely 2; sheath broad, usually indistinguishable from the gelatinous 

 matrix of the thallus; propagation by the division of a cell alternately in 

 two directions in the same plane, and by the production of biciliate 

 zoospores, one from each cell; reproduction by copulation of micro- 

 zoospores. 



Etymology: Greek Terpa-, four, and anopa, seed. 



Tetraspora explanata Ag. Flora II., G42. 1827. 



Thallus irregularly expanded, lamellose, smooth, green, attached or free; cells 



elliptical or globose, 5-7 fi in diameter, usually arranged in twos. 

 In stagnant water, Minden. 



Tetraspora lnbrica (Roth.) Ag. Spec. Alg. L, 415. 1821. 

 Conferva lnbrica Roth. Catal. III., 103. 



Thallus elongated, tubular, erect, even 2 decimeters long. 2-10 mm. broad 

 variously lobed and sinuate, subgelatinous, yellowish-green; cells globose 

 or angular usually in fours, 7-11 /j- in diameter. 

 In standing water, Lincoln. PI. IV., Fig. 1. 



3. CHABACIUM A. Br. in Kuetz. Sp. Alg. 208. 1849. 



Cells solitary, always attached at one end, stipitate; cell contents homogene 

 ous or granular; pyrenoids single or several; propagation by division of 

 the cell contents into zoospores. 



Etymology: Greek, diminutive of x a l><^, a pointed stake. 



< 'haraei naegelii A. Br. 1. c. 



Cells elliptical or oval, when fully developed 2 or 3 times longer than 

 broad, with arounded apex; stipe short, not dilated at base; cell-contents 

 bright green, granular; diameter of cells 7 Is . 



On filaments of Mesocarpus, Lincoln, South Bend. PL 1\\, 1 i. 



4. TETRAEDOX Kuetz. Phycol. Germ. 129. 1845. 



Cells single, segregate, free-swimming, compressed, 3 B-angled; angles more 

 or less produced, sometimes radially elongated, either entire or bifid, 

 mostly armed, rounded or truncate at the ends; cell membrane thin, 

 even; cell contents chlorophyll-green, granular, usually with a few red 

 dish oil drops; propagation by the Formation of three or more gonidia 

 in each cell. 



Etymology: Greek rtr^a—, four, and . base. 



Tetraedon trigonnm (Naeo.) Hanbo. Hedwigia, 1888, p. 130. 



Polycdrium trigonum Naeo. Gatt. EinzelL Alg. si. 1849. 



Cells somewhat compressed, 3-5-angled; angles obtuse, muoronate. 



