CHARA BRAUNII. 13 



ridges terminating iu short basal claws ; outer membrane 

 thick, brittle, semi-rigid, semi-opaque, dull brown to black, 

 finely and faintly granulated. Antheridium c. 250-275 (x 

 in diameter. 



Habitat. — In a canal in tepid water. 



Distribution. — England : South Lancashire, near 

 Eeddish (C. Bailey, 1883); still there in 1920 {F. J. 

 Stubbs). 



First record : ' Journ. Bot.' 1884. 



Outside the British Isles C. Braunii is very widely dis- 

 tributed, occurring in Norway, Sweden, Finland, Russia, 

 Spain, Portugal, France, Belgium, G-ermany, Austria, 

 Italy and Greece, also in many parts of Asia, North and 

 South Africa, North and South America, Australia, New 

 Zealand, and the Sandwich Islands. 



A medium-sized plant, often tufted in growth, sometimes 

 sliglitly incrusted, the incrustation tending to become annular. 

 Readily distinguished from any other British species by the 

 entire absence of cortex, the clear transparent green flexible 

 stems and branchlets and the long segments of the latter, which 

 combine to give the plant a close resemblance to a Nitella. The 

 small conical terminal segment, similar to and but little larger 

 than the two or three developed bract-cells at the ultimate 

 node, form with them a distinctive corona-like termination to the 

 branchlets. The frequent production of a pair of oogonia and 

 a pair of antheridia at the same node is also characteristic ; 

 occasionally there are even three of each of these organs together. 

 The shape and dimensions of the oogonium and oospore and the 

 number of convolutions shown are very variable ; those given 

 here are taken from the British plant. Dr. Allen, in Iris paper 

 on the American forms ('American Naturalist,' XVI, pp. 358-369, 

 t. 4, 1882), gives an excellent account of the variation. 



C. Braunii is the only representative in this country of the 

 group HaplostepJianai, of which there are many species, especially 

 in warmer latitudes. In the British Isles it has been found in 

 the one locality only, occurring in a canal, the water of which is 

 raised to an abnormal temperature by the discharge of hot 

 water from adjacent mills. Naias graminea, a native of Egypt, 

 has been found in the same neighbourhood, and as its introduc- 



