NOSTOCE^E. 239 



Uncertain Species. 

 Anabaena inaequalis. (Ealfs.) Braun., in litt. 



Forming extensive strata consisting of thick gelatinous masses 

 of a deep green colour. 



Trichomes stout, moniliform, elongated, joints distinct, at first 

 quadrate, finally orbicular, with granular contents. Heterocysts 

 globose, broader than the ordinary joints, occurring at short 

 intervals. Spores 3-4 times longer than broad, with truncate 

 ends, in chains of two to five. 



SIZE. Not determined. 



Dolicliospermum incequale, Ralfs Ann. Nat. Hist. 1850, 335, 

 t. 9, fig. 1. 



Sphcerozyga incequalis, Kutz. Tab. Phyc. i., t. 96. Rabh. 

 Alg. Eur. ii., 194? 



In boggy pools. 



We have seen no specimens of this, or of Kutzing's Splicsrozyga 

 incequalis, and therefore cannot pronounce on their identity. Mr. Ealfs 

 says that " this plant forms extensive strata, composed of thick 

 gelatinous masses of a deep green colour. Filaments elongated, con- 

 sisting of from 100 to 200 cells, and, being stouter than in most species 

 belonging to this genus, visible to the naked eye. Ordinary cells dis- 

 tinct, quadrate in immature specimens, but at length nearly spherical, 

 appearing punctate on account of the scattered granular matter which 

 they contain. Vesicular cells (Heterocysts) spherical broader than the 

 ordinary joints and occurring at short intervals. Spores 3 to 4 times 

 longer than broad, with truncate ends ; in chains of from two to five 

 members." May be known from A. Ralfsii by its spherical heterocysts 

 and catenate spores. 



Plate XC11L fig. 4. Trichomes with heterocysts and spores X 400 ; 

 after Ealfs. 



GENUS 96. APHANIZOMENON. Morren. (1839.) 



Thallus membranaceous, free swimming, bright blue, blue 

 green, or becoming olive. Trichomes medium size, a little 

 attenuated towards the apex, agglutinated parallelly and very 

 densely in fascicles, joints cylindrical, very closely connected, 

 pale blue, nearly colourless and delicately granular. Spores 

 elongated, cylindrical, rounded at the ends, pale blue, or some- 

 what olive, exospore thin, quite smooth. Borzi Alg. Ficochrom. 

 p. 279. 



Thuret places this genus next to Analaena, but, in the absence of 

 heterocysts, it seems that its proper place would be in Lyngbyte, allied to 

 Oscillaria. We have retained it here, in preference to altering the " key 

 to the genera," which is given on page 221. 



