ADDENDA. 259 



of apical vacuoles, and the concave ends of the chloroplast. 

 The new diagnosis is therefore as follows : 



ROYA W. & (.1. S. W. emend. Hodgetts.* Cells un- 

 constricted, cylindrical or subcylindrical, straight or 



/ / Q^7 



slightly curved, gently attenuated towards the apices, 

 which are more or less truncate or obtusely rounded ; cell 

 wall smooth, colourless, without pores ; chloroplasts 

 one in each cell, or, in old cells, divided at the middle, 

 axile, either rounded at the ends and extending to the 

 apices of the cell, leaving no colourless space, or with 

 concave extremities, in which case the cell has an apical 

 locellus at each end ; nucleus either lateral, lodged in a 

 tiny excavation of the chloroplast, or median, between the 

 two chloroplasts ; pyrenoids several, in a median series. 



Roya anglica West. 

 (PL CLXVI, figs. 11-13.) 



Roya aitylica West, Hodgetts in Journ. Botany, Iviii, 1920, p. 69. 



Cells cylindrical or subcvlindrical, unconstricted, 5- 



*/ -' 



15 (-20) times longer than broad, very slightly tapering 

 towards the apices, which are sub truncate, sometimes 

 straight, but usually slightly asymmetric, a slight 

 regular curvature being present ; greatest width of 

 cell not always in the middle, but more towards one 



\j 



end than the other ; in extreme cases almost clavate 

 in shape ; chloroplast axile with ? 4 longitudinal ridges, 

 usually one in each cell with a slight lateral concavity 

 for the nucleus, afterwards divided at the middle with 

 the nucleus between the two halves ; pyrenoids 4-6 

 in a longitudinal series ; chloroplasts concave at the 

 extremities, leaving room for an apical vacuole, without 

 moving granules ; cell-wall smooth, colourless, slightly 

 thickened at the apices. 



Zygospore globose and smooth. 



Length 35-80 (-112) p ; greatest width 7'5-9{Jt; 

 breadth of apices 5-7 JJL ; diam. zygosp. 20-26 p. 



ENGLAND.- -Quinton, near Birmingham, Worcs ! 



* In 'Journ. Botany,' Iviii, p. 69, 1920. 



