ROYA. 109 



o. Roya Pseudoclosterium (Roy) West & G. 8. West. 



(PL X, fig. 30.) 



Closterium Pseudoclosterium Eoy in Eoy & Biss. Scott. Desm. 1894, p. 



247 ; Norclst. Index Desm. 1896, p. 208. 

 Roya Pseudoclosterium West & G. S. West, New and Int. Freslnv. Alg. 



i.s9(i, p. Io3 ; Alga-fl. Yorks. 1900, p. 48 ; Alg. X. Ireland, 1902, p. 22.' 



Cells very slender, elongate, cylindrical, 4060 times 

 longer than their diameter, almost straight, apices 

 truncately rounded ; chloroplast with 4-6 pyrenoids. 



Zygospore unknown. 



Length 96-192 ^\ breadth 2'6-3'5 fi. 



ENGLAND. Pilmoor, 1ST. Yorks ! 



WALES. "North Wales" (#/>//). 



SCOTLAND. Slewdrum and Upper Powlair, Aberdeen ; 

 Cammie, Kerloch, Muiryhangh, and Dalbrake, Kincar- 

 dine (If ">/ & Bissett). Rhiconich, Sutherland! 



IRELAND. Near (Plenties and Lough Anna, Donegal ! 



Genus 9. CLOSTERIUM Nitzsch, 1817. I 



Nitzsch, Beitr. zair Infusor. oder Natnrbeschr. der Zerkarien iind Bazil- 



larien, 1817, pp. 60 and 67. 

 Corda, in Alman. de Carlsbad, 183o, p. 193. 

 Menegh. Synops. Desm. 1840, p. 229. 

 Ealfs, Brit. Desm. 1848, p. 159. 

 Kiitz. Spec. Alg. 1849, p. 163. 

 Arch, in Pritch. Infus. 1861, pp. 720 and 74U. 

 Babenh. Flor. Europ. Algar. Ill, 1868, p. 123. 

 Kirchn. Alg. Schles, 1878, p. 137. 

 Gay, Monogr. loc. Conj. 1884, p. 39. 

 Wolle, Desm. U.S. 1884, p. 37. 

 Cooke, Brit. Desm. 1886, p. 17. 

 De Toni, Syll. Alg. 1889, p. 817. 



Cells elongated, always more or less attenuated, 

 generally curved and often strongly arcuate or lunate, 

 unconstricted ; poles obtuse, truncate, rostrate or at- 

 tenuated to fine needle-like points ; cell-wall smooth or 

 striated, often brown or yellow-brown in colour ; one 

 chloroplast in each semicell, with a variable number of 

 longitudinal ridges ; pyrenoids few or many, in a single 

 axile series or scattered irregularly through the chloro- 



o / o 



plast ; with a terminal vacuole between the end of the 



