STAUPxASTRUM. 93 



acute and rectangular, minutely excavated at its apex ; 

 semicells elliptical or subsemicircular, dorsal margin only 

 slightly convex, ventral margin very tumid ; each angle 

 of the semicell with a pair of short smooth processes, all 

 lying in the same horizontal plane, very slightly diver- 

 gent ; apices of processes bifid, with the two teeth 

 vertically one above the other. Vertical view 3-5- 

 angular, sides strongly concave, angles deeply lobed, 

 each lobe tapering into a short process. Cell-wall 

 smooth. Chloroplast axile, with a central pyrenoid in 

 each semicell. 



Zygospore spherical, with a number of slender pro- 

 cesses which are twice dichotomous at the apex. 



Length, with processes, 22-27 'O\L ; breadth 23-28 [i ; 

 breadth of isthmus 7-8 [JL ; diam. zygosp., without pro- 

 cesses, 18 (JL ; with processes, 30-35 \i. 



ENGLAND.- -Xear Bowness, Westmoreland (Bissett). 

 Strensall Common (W. B. Turner) and Pilmoor, N. 

 Yorks (very abundant and with zygospores) ! Thursley 

 Common, Surrey (very abundant) ! Dartmoor (Harris). 

 WALES. Cape! Curig, Carnarvonshire (Cooke & Wills). 

 Outlet of Llyn Gwernan, Dolgelly, Merioneth (Rolfs). 



SCOTLAND". Loch Inver, Sutherland ; Birsemore Loch, 

 near Loch Dawan and Tomacher, Aberdeen; near 

 Durris Bridge, Kincardine (Roy & Biss.). 



IRELAND. Achill Isle, Mayo ! Adrigole, Co. Cork ! _ 

 Geogr. Distribution. France. Germany. Galicia in 

 Austria. Norway. Sweden. Denmark. Bornholm. Java. 

 Australia. United States. Brazil. 



SECTION I. 



Processes rough, denticulate or spinate along their whole length 

 * Cells without prominent accessory spines on 



cell which, at the most, is rough with tiny granule 

 more acute denticulations, never bearing spine; 

 great length. 



