192 



NOTES ON SOME BRITISH SPECIES OF CALLITRICHE 



from the point of insertion of the styles. Styles are terminal, about 3 mm. long and 

 persistent. 



Bracteoles (Fig. 2C 5 and 6) 



Bracteoles large, those of the female being straight and those of the male slightly 

 falcate. 



Stamens (Fig. 2C 6) 



Filaments 4-5 mm. long, anthers large. 



Chromosome number 

 2n = 10. 



D. Callitriche hermaphroditica 

 Leaf form (Fig. ID) 



Linear leaves only are described (this plant having been found by the writer always 

 submerged). The leaf is about 1 cm. long and about 1-5 mm. broad . The leaf is broader 

 at the base than at the tip and is characteristically curved downwards towards the base 

 of the shoot. Leaf 1 -veined. 



Fruit form and styles (Fig. 2D 1-4) 



Fruits 2-7 mm. long by 2-8 mm. broad. The size of the fruit alone is sufficient to 

 identify this species. In face view the fruit is narrowed slightly towards the base. Grooves 

 are very conspicuous, the lobes being produced into well-marked wings with sinuate 

 margins. Wings are divergent. Styles are lateral, about 2 mm. long and fall early. 



Bracteoles 



Bracteoles are absent. 



Stamens (Fig. 2D 6) 



Filaments are short (1-2 mm.) and anthers are small. 



Chromosome number 

 2n = 6. 



REFERENCES 



BUTCHER, R. W. & STRUDWICK, F. E., 1946, Further Illustrations of British Plants. Ashford. 

 CLAPHAM, A. R., 1952. in Clapham, A. R., Tutin, T. G. & Warburg, E. F., Flora of the British Isles. 

 Cambridge. 



HEGELMAIER, F., 1864, Monographic der Gattung Callitriche. Stuttgart. 



JONES, H., 1955, Heterophylly in some species of Callitriche, with especial reference to Callitriche inter- 

 media, Ann. Bot., N.S., 19, 225-245. 



PEARSALL, W. H., 1934, The British species of Callitriche, Rep. Bot. Soc. & E.C., 10, 861-871. 



SAMUELSSON, G., 1925, Die Callitriche-Arten der Schweiz. Festschrift Carl Schrdter, 3, 603-628. 

 Zurich. 



SCHOTSMAN, H. D., 1954, A Taxonomic Spectrum of the Section Eu-Callitriche in the Netherlands, 



Acta Botanica Neerlandica, 3, 313-384. 



