SPHAEROZYGA. 289 



Syn. Trichormus incur vus. All man. 



On the trunks of trees, low down near the water's edge in 

 swamps, New Jersey. 



Plate CXCYIII, figs. 1, 2, specimens of filaments. 



i 



Genus 95, SPHAEROZYGA, (Ag. ) Ealfs. 



Trichomes sheathless, singly, or agglutinated in an indefinite 

 gelatinous stratum ; rarely a number enclosed in a definite tegu- 

 ment ; cells spherical, elliptic or oblong, or transversely com- 

 pressed. Heterocysts intercalated, binary or solitary. Spores 

 proximate to the heterocysts. 



SPHAEROZYGA POLYSPERMA, Kg. 



Filaments subsolitary or associated and interwoven, light 

 bluish green, straightish, or variously curved and flexuous ; 

 articles, either subspherical or shortly cylindrical ; hetero- 

 cysts globose or very broadly elliptical ; a little larger to 

 twice the diameter of the vegetative cells ; spores more or 

 less, elongate, cylindrical ; in the mature state dark bluish 

 green, densely granulate and with rather thick membrane. 



Diameter of vegetative cells, 2.5-6 yw. 



Syn. Splwerozyga Carmichaelii, Harv. ; Cylindrospermum elonga- 

 tum, Kg.; Sph. Flotomana, Kg.; Dolychospermum poly- 

 spermumj Wood. 



Small pools, stagnant waters. 

 Plate CXCVIII, figs. 37, 38, two short filaments. 



SPHAEROZYGA HASSALLII, Bab. 



Trichomes equal, curved, often circinate, interwoven into 

 a thin aeruginous stratum ; joints globose or more or less 

 compressed, delicately granular ; heterocysts spherical, color- 

 less, intercalated without order ; spores oblong cylindrical, 

 single or in pairs, sometimes in series, distinctly curved, dark 

 aeruginous, densely granulated, 2-3 times longer than broad. 



Diameter of cells, about 8 /* ; heterocysts, 9-10 ju ; spores, 

 12 //. 



Syn. Anabama flos-aquae, Hass. ; Ana. Hassallii, Nord. and 

 Wittr. ; Dolychospermum Thompson^ Ann. Nat. Hist.; 

 Anabcena circinalis, Phillips. 



Plate CXCVIII, figs. 33-35, three specimens from many 

 variable forms ; fig. 36, Oseillaria filaments resulting from the 

 development of this Sphaerozyga. 



