36 BRITISH CHAROPHYTA. 



stem a strongly ribbed appearance, and renders the spiral 

 torsion very conspicuous. The presence of an ascending cortex to 

 the lowest branchlet segment is apparently peculiar to this species. 



The upper segments of the branchlets, especially in the Lough 

 Ennel plant, are often much enlarged and extremely turgid. 

 Sometimes only the lowest segment is corticate when the plant 

 looks curiously unlike any other European species. 



C. tomentosa does not fruit freely and, although both sexes 

 occur in Ireland, we have not found ripe oogonia, hence the 

 description of the oospore has had to be drawn up from Con- 

 tinental specimens. 



A slender form from a dyke off Lough Owel (Groves, ' Char- 

 Brit. Exs.' No, 41) has small bract- and spine-cells. A very 

 extreme form, f. heteromalla Braun, from Pomerania has the 

 spine-cells much reduced, and the bract-cells narrow, the anterior 

 only being developed. Braun states that the stipalodes are 

 sometimes in three rows, and Dr. Migula figures a node with 

 a triple circle. Herr Adolf Witt has written an account of the 

 vegetative histology of this species.* 



Braun, Migula and others have employed Wallroth's name, 

 C. ceratophylla, published in 1815, although antedated by C. 

 tomentosa Linn. (1753) and C. latifolia Willd. (1809). Hudson 

 and some other early authors applied the name C. tomentosa to 

 forms of C. hispida, misled probably by the synonyms quoted 

 by Linnaeus. As regards the identity of Linneeus's own plant, 

 there can be no doubt. The character "aculeis caulinis ovatis"' 

 would hardly be applied to any other than the present species, 

 and the identification is confiimed by the specimen in the Linnean 

 herbarium. The two synonyms which Linnaeus quotes res- 

 pectively from Morison and Plukenet are ambiguous, and in 

 neither case does the author's figure suggest the present plant. 

 In Wallroth's otherwise admirable plate the plant is represented 

 as monoecious. 



B. Monoecise. 



7. Chara contraria Kiitzing. 

 (Plate XXXIII.) 



Chara fostida vai\ 'moniliformis Beatjn in Ann. sc. Nat. ser. 2, I, p> 

 355 (1834) ; in Flora, XYIII, i, p. 63 (1835). 



* ' Beitrage zur Kenntnis von Chara ceratophylla Wallr. and C. crinita 

 Walk.,' Leipzig, 1906. 



