CLUST KIM TM. 183 



Int'u.^ isiil, p. 7 !'.; Eabenh. Flor. Euro]). Al^ar. Ill, 1868, p. l:;r> ; 

 Wul.1... DCSIM. U.S. issi., p. 4(5, t, 7, f. Ki; Cooke, lirit. Dusui. 188<>, p. :;:.', 

 t. 11, f. 1', t. 15, T.S; I Lmsi,'. Proctr. Al-vntl. liulnn. isss, p. ls:5 ; I),- T,,ui, 

 Syll. Ali;-. ISM I, p. M7 -, Roy & Biss. Scott. D.-sm. IS'.H, p. l' 1-s ; N,,i.l i 

 ln.l.'x Desm. I S;M;, p. 220; West & G. 8. Wc.st, Aly. S. England, 18U7, 

 ].. IM' ; Al^-u-H. Yurk. 1900, p. 57. 



C/. h'l.ilj'aii 1>. li/i'irinn Klebs, Desm. Ostpruuss. 1879, p. 18, t. 2, f. 6 6, c. 

 H'tl/sii Kuntze, Kevis. gen. plant. 1891, p. 884. 



( Y'lls laru.'C, G 8 times longei- than their diameter, 

 moderately curved, outer margin about o-3 of are, 

 inner margin much inflated for over half the length of 

 the cell, somewhat suddenly attenuated towards the 

 extremities, which are drawn out, somewhat narrow, 

 and slightly incurved ; apices obtuse ; cell-wall finely 

 st riated, 28-33 striae visible across the cell, yellow- 

 brown or reddish-brown in colour; chloroplasts 

 obscurely ridged, with a median series of about five 

 pyrenoids; terminal vacuole with four or five large 

 moving granules clustered together to form a single mass. 



Zygospore unknown. 



Length o 1 5-454 /u; breadth 42-50 /x; breadth of 

 a])ices 9-10 /a. 



ENGLAND.- -Westmoreland! (7iV//'s). Lancashire 

 (/.WA-). W. Yorks ! Norfolk (CooJce). Sussex 

 (Ralfs). Kent! (lllfis). Cornwall (Mar quand) . 



WALKS. - - Carnarvon (Ittilfs) and Capel Curig ! 

 (Coulee fy ir/7/.v), Carnarvonshire. Dolgelly, Merioneth 

 (Ralfs). 



SCOTLAND.- -Ross, Aberdeen, Kincardine, Forfar, 

 ^Vrgyll (Ifot/ $' Pissett). Rhiconich, Sutherland! 



di'aijr. Distribution. France. Grermany. Austria 

 and Gralicia. Norway. Sweden. Bornholm. Iceland. 

 ( i reenland. Siberia. Australia. Central Africa. 

 United States. Brazil. 



The type of Cl. llalfxii is one of the rarest and most 

 striking of British Closteria. We have 1 seen very few speci- 

 mens of it. 



Var. hybridum Rabenh. (PI. XXIV, figs. 8-18.) 



Closterium Ral/sii var. hybridum Kabenli. Krypt. Fl. Sachs. ISO:!, p. 171 ; 

 Flor. Europ. Algiir. Ill, 1868, p. 135 ; DJ Toui, Syll. Aly. iss'j, p. 



