Fresh-water Alga? of Canada. 335 



the descriptions given by Hassall in his valuable volumes on the 

 " History of the British Fresh- Water Algw." This is the best and 

 most systematic treatise which we have on the subject. It was 

 first published in 1845, and is much in advance of any similar 

 work up to that time. It, however, now requires to be re-edited, 

 and its descriptions and figures carefully revised. It is to hoped 

 that the author may yet meet with sufficient inducements to lead 

 him to undertake a new and enlarged edition. 



The three main divisions into which Hassall divides this order 

 of plants are : — 



I. Alg^e filiformes. II. Alg^e globulifer^e. III. Alg^e 



FIGTJRAT^E. 



Under the first of these divisions we have 



Family I. Siphoned. 



Characters. — Algse composed of a continuous branched and cylin- 

 drical cell, inarticulate. Reproductive organs external. 



Genus I. Vaucheria, D. C. 

 Characters. — Frond here and there, occasionally inflated. Repro- 

 ductive organs of two kinds capsules ? and anthero3 or horns 

 lateral or terminal. 

 This is both a curious and highly interesting plant. It is gen- 

 erally found in quiet pools and ditches with muddy bottoms, into 

 which it strikes its roots. It grows in masses, in its young state 

 is of a bright velvety green, but on attaining maturity it takes a 

 light-olive colour. The organs, which are described as reproduc- 

 tive, are very singular in appearance, and quite peculiar to this 

 genus. These consist of capsular bodies, either terminal or pro- 

 jecting from the main stem, at nearly right angles. In fructifica- 

 tion the contents of the more or less enlarged extremities of the 

 branches or special projections separate from the general contents 

 of the plant, condense into a globular green mass, and become a 

 spore, which, at length, escapes by a rupture of the walls, moves 

 freely about in the water, in a short time becomes fixed, and de- 

 velopes into a new plant. This was at one time thought to be 

 reproduction without fecundation. But Vaucher, in 1803, observed 

 attached to the capsular bodies which spring from the sides of 

 the plant, horn-shaped projections, which he conjectured to be 

 analogous to anthers. No observer had, up to a recent date, been 

 able to verify his observations, and doubt was cast upon their 



