64 BRITISH CHAROPHYTA. 



The form regarded as the type is a medium-sized rather neat- 

 looking plant, the internodes of the upper part of the stem 

 usually not much exceeding the branchlets. the stem very 

 brittle, the branchlets usually nearly straight. The plant is 

 often inerusted but rarely to the extent of the diplostichous 

 species. It does not apparently form tufts like C. delicatula, 

 and bulbils do not seem to be often produced, but unfortunately 

 many of the herbarium specimens are lacking in the rooting parts. 

 Though both circles of stipulodes are normally quite rudimen- 

 tary, it occasionally happens that one, or two, belonging to the 

 upper circle is elongated. 



The varietal name capillacea has been applied to very slender 

 forms, of both this species and C. delicatula. 



Owing to the fact that this and the following species have 

 hitherto been generally combined under the name of C. fragilis 

 in this country, we have not been able to apportion all the older 

 records, so that the particulars of their respective distribution 

 and synonymy are incomplete. 



Desvaux's name for the species is so generally adopted that 

 we hesitate to supersede it by either of the earlier ones given by 

 Thuillier, and in consequence have treated the smaller, less 

 extended forms as representing the type, rather than the var. 

 Hedwigii. The latter is, however, the more vigorous and highly 

 developed form, and if Thuilher's name of C. globularis is adopted, 

 will stand as the type. For this reason we have chosen it for 

 the illustration of the species. 



A curious almost entirely sterile plant with subtriplostichous 

 stem-cortex and ecorticate branchlets collected by Abram 

 Sturrock in Monk Myre, a small loch in East Perth, was 

 described by H. & J. Groves (' Journ. Bot.' XXII, p. 2, 1884) as 

 var. SturrocMi of C. fragilis. We think this may probably be a 

 hybrid with one of the Diplostichse, the stipulodes resembling 

 those of some species of that section. 



Var. b. Hedwigii. 

 (Plate XLIII.) 



C. glohularis Thuillibr PI. Env. Par. ed. 2, p. 472 (1799). 

 C Hedwigii Bbtjzblitts Obs. Char. pp. 7, 21 (1824). 



Hooker Brit. M. II, p. 245 (1833). 



Bbekblbt in Engl. Bot. Suppl. 2762 (1834). 



KiJTZiNG Tab. Phyc. VII, t. 55, f. 1 (1857). 

 C fragilis var. Hedwigii KiJTZiNG Phyc. Gen. p. 319 (1843J. 



Lange in Plora Danica, 2797, f. 2 (1869). 



