HASSALLIA. 231 



23. HASSALLIA Berk. 



Char. " Branches increasing by the elongation and division 

 of a single cclU' — Berk. 



The above definition, like that of Scgtonema, embraces only 

 the essential character of the genus, to it, other well marked 

 peculiarities maybe added; such'as the rigidity of the filaments, 

 the branches usually solitary, and the beaded form of the cells. 

 The genus therefore may otherwise be defined thus : — 



Char. Filaments somewhat rigid, of tmequal diameter. 

 Branches usually solitary, formed hy the elongation and 

 division of a single cell. Cells distinctly moniliform, usu- 

 ally in a single series. 



Kiitzlng's genus Sirosyphon is thus specified : it includes 

 but a single species, and cannot be said to fulfil the intention 

 of the genus Hassallia. 



*' Trichomata parenchymatica ex cellulls gellneis in vagina 

 lamellosa, aplce clausa longitudlnaliter striatis, apice in arti- 

 culos epenchymaticos confluentes trauseuntibus compositum. 

 Spermatia iusterstitialia. Rami basi genlculati." 



The above characters seem to me to be only of specific and 

 not generic importance. 



The genus Hassallia was instituted by the Rev. ]\Ir. 

 Berkeley a considerable time ago : that gentleman, however, 

 delayed publishing it, and conceived on the appearance of the 

 " Phycologia Generalis" that it was frustrated by Kutzing's 

 genus Sirosyphon, which I cannot think that it is. 



1. Hassallia ocellata Hass. 



Plate LXVII. Figs. 2. 7. 6. 



Char. Branches solitary, divaricating, slightly contracted at 

 the base. Cells beaded. 

 Conf. ocellata Dillw. t. D. Co7if. ocellata E. B. t. 2530. ; 

 Harvey, In Hook. Brit. Fl. p. 364. Scytonema ocellattnn 

 Harv. in Manual, p. 154. 

 Q 4 



