140 BRITISH CHAROPHYTA. 



apex ; coronula large and conspicuous, c. 75-90 /A high, 

 100/x broad, the upper cells tapering and converging, 

 forming a rounded apex, usually deciduous. Oospore 

 globose-ellipsoidal, c. 400-475 ^ long, 350-450 p. broad, 

 when ripe dark wine-red, showing about 9 fine ridges ; 

 outer membrane semi-rigid, transparent or semi-opaque, 

 wine-red or dark red, smooth or sometimes exhibiting 

 scattered tubercles. Antheridium large, attaining some- 

 times a diameter of c. 550 //,. 



DISTRIBUTION.- -Ireland : in a lagoon north of Wexford 

 Harbour, Co. Wexford (Rev. E. S. Marshall, 1896). 



Outside the British Isles T. nidiftca occurs in Nor- 

 way, Sweden, Finland, Russia, Denmark, France, and 

 Northern Germany, growing in some localities in the 

 Baltic Sea. A form (f. antaretica Braun & Nordstedt, 

 Nitella antaretica Braun oliiii) has been found in 

 Kerguelen-land. 



A small to medium-sized plant but sometimes attaining a 

 height of 20cm.; of a dark brownish-green, usually un- 

 incr listed. Closely allied to T. glomerata from the more 

 typical forms of which it differs in the larger, broader 

 oogonium, the taller coronula which is conspicuously rounded 

 above, the larger and broader oospore, which when ripe is of 

 a rich wine-red colour, with a shining surface, the membrane 

 being destitute of decoration. The antheridium also attains to 

 a larger size. The rays of the fertile branchlets are strongly 

 incurved and frequently stout, with cells rounded afc their 

 extremities ; the rays are conspicuously constricted at the 

 joints, and tlie apical cell is often quite short. 



The only plant from the British Isles which cau be con- 

 fidently referred to this species is that collected by Mr. 

 Marshall at Wexford, which was unfortunately in too far 

 advanced a condition to admit of its being satisfactorily 

 figured. The drawing of the plant the natural size had 

 therefore to be taken from a foreign specimen. The Wexford 

 plant belongs to a large form and is much incrusted. 



A Tolypella was collected in Lough Neagh, near Langford 

 Lodge, by Dr. Moore in 1840, which was referred by Braun 

 with some doubt to T. nidifica. In ' Fragmente,' p. 94, as 

 already stated (p. 138), this is placed under var. intermedia of 



