J. SAUXDERS — NOTES ON THE CHARACEJE. 21 



a constant relation to the branchlcts in the -whorls, this peculiarity 

 is used in the classification of these plants. Other points are the 

 characters of the coronula, the relative position of tlie nucules and 

 globules, and the number of cells in the ultimate branchlets. 



In the younger cells the plienomenon of cyclosis, or circulation 

 of the protoplasmic contents, can be observed. To succeed in this 

 may require some amount of patience, as the motion may be 

 arrested in preparing the specimen for examination. After a time 

 the granular contents of each cell will be seen to move slowly 

 along one side, to traverse the width of the cell at one end, and 

 then to continue its course along the other side. These movements 

 continue indefinitely and are in one direction. In this respect they 

 agree with the same phenomenon as seen in Elodea, and differ from 

 it as it occurs in the Mycetozoa, in which the circulation is 

 alternately in opposite directions. This display of energy is most 

 evident in the youngest cells. Is it therefore connected with 

 gi'owth ? It can hardly be an accompaniment of assimilation, for 

 it is visible with artificial light other than electric. 



One of the unsolved problems in the life-history of the Characeae 

 is the irregularity of their appearance. It does not follow that 

 because a certain species occurs in a pool in any one year it will 

 reappear the next year, and this notwithstanding the vast number 

 of fruits which lie in the mud from the previous season's growth. 

 It has been suggested by the Messrs. Groves that the excessive 

 development one year may exhaust that particular station of 

 certain constituents necessary for the growth of these plants. 

 This will probably account for the phenomenon in cases where, 

 after a season of abundance, they are absent for several successive 

 years. It does not, however, cover the whole field of observation, 

 for they may be singularly persistent even in a very small area, 

 the same species occurring for several seasons in succession. 



The following notes, although referring only to a portion of 

 South Beds, were carefully taken and will illustrate the foregoing 

 remarks. 



In 1883 Chara vulgaris nearly filled a pond at Great Braming- 

 ham, and fruited abundantly. It died away in situ, and did not 

 reappear the next season. Up to 1895 not a trace of it has been 

 visible, although the spot has been frequently examined. The 

 mud of the pool must have been crowded with ripe nucules in 

 an environment apparently favourable to germination. The pond 

 here referred to, as well as the others on which observations were 

 made, were but little liable to interference by artificial agencies. 



Chara hisjjida, which is the largest British species, seems fairly 

 constant in its occurrence, as it has grown for several years in 

 succession in ponds at Tottemhoe. In one pool it has been remark- 

 ably persistent, but in 1895 the quantity of it was diminished, as 

 it was choked by the excessive growth of sedges. 



Nitella opaca grew in Reed Pond, Sundon, in 1883 and 1884, 

 but was absent for several years afterwards. In another pool near 

 this one N. opaca was abundant in 1885, but it was replaced by 



