64 BRITISH CHAROPHYTA. 



British Isles, is widely distributed, occurring in 

 almost all the countries of Europe, and in Asia, 

 Africa and North America, while the male plant is 

 extremely rare and has been found only in a very few 

 localities ; yet perfectly well-developed oospores are 

 produced from the unimpregnated oospheres in great 

 abundance, in fact it is one of the most freely 

 fruiting species. The following interesting particulars 

 are given by De Bary in ' Zur Keimungsgeschichte 

 der Charen ' as translated by Hemsley in ' Journ. 

 Bot.' xiii, p. 299 (1875) : 



" Respecting this phenomenon the examinations 

 revealed the fact that the ovule-bud originates in 

 precisely the same positions, and its development is 

 exactly as in the other monoecious and dioecious 

 species of the genus ; further the neck parts into 

 five clefts before ripening, as in other Charas before 

 impregnation. These clefts are indeed small, though 

 not smaller, for instance, than in C. scoparia. More- 

 over it was most satisfactorily demonstrated that the 

 ripening of the oospores of isolated female plants under 

 continual control neither showed any trace of antheridia, 

 nor were there any antheridia-bearing plants near 

 them. It may be asserted without exaggeration that 

 under good culture scarcely a single oospore fails to 

 germinate. The female plant growing wild is more 

 fertile than any of its congeners, although the male 

 plant, with the exception of some herbarium specimens 

 mentioned by Braun, is unknown. Finally it was 

 proved that the oospores mature on isolated female 

 plants under the most perfect control would germinate. 

 Ripe oospores were taken on November 10 from plants 

 isolated on the 9th of the preceding July. They 

 germinated at the beginning of April, and produced 



