BOTRYDIUM GRANULATUM. 107 



The following is Reinsch's account of this, given in his " Die 

 Algenftora des mittleren Theiles von Franken," &c, pp. 218, 219: — 



" The plant about 1^ rn.m. diam. ; the upper portion, or that 

 above ground, globular, gradually narrowing downwards, and pas- 

 sing into one or two principal roots, which become gradually rami- 

 fied into many fine rootlets ; the chlorophyll-contents at the begin- 

 ning dense and homogeneous, and, clothing the inner cell-membrane, 

 extends only to the neck of the root ; the membrane is rather rigid, 

 upon being broken the cell-contents become extruded, the membrane 

 collapses as a thick pellicle, whose contents admit of being com- 

 pletely pressed out ; the fluid contents in this condition consist of 

 finely-granular plasma, tinged by chlorophyll-granules. (Subse- 

 quently the green plasma layer becomes separated from the mem- 

 brane, breaks up into single equal-sized portions, which become 

 rounded off, coated with a membrane, and gradually individualized 

 as daughter-cells. At last the entire globose cell is densely filled 

 with rounded daughter- cells ; whilst, previous to this state, the 

 plant presented an intensely grass-green colour, it shows in this 

 latter state a clear or sea-green colour ; mature and immature plants 

 hence readily admit of being distinguished by the tint with the 

 unassisted eye. The membrane of the mother-individual at last 

 passes to decay, it collapses, and the daughter-cells become the 

 germs of new individuals in the soil. The maturity of the indi- 

 viduals occurs towards autumn, and accordingly the germ-cells lie 

 resting in the earth during winter, and germinate in the following 

 spring. The development of the germ-cells to new individuals 

 takes place without formation of a * prothallus, ' (" ohne Vorkeim- 

 bildung.") One end elongating as a root at once penetrates the 

 earth, the other end becomes developed as the above-ground por- 

 tion. The diameter of a ripe germ-cell is 0.009-0.012 rn.m. The 

 plants prefer to establish themselves on the surfaces of the large 

 clefts which are produced when the waters retreat and the ground 

 becomes gradually dried by the air." 



The author refers to Cienkowsky's observations on " Protococcus 

 botryoides." (Bot. Zeit. 1855.) This original paper I had not before 

 seen ; but at this point I stopped writing this letter, and went to the 

 Royal Dublin Society's Library and fished it up. Berkeley, I fancy, 

 is right in supposing this really refers to a Botrydium. Cicn- 

 kowski's figure of his plant shows " resting-spores " and " swarm- 

 spores." His fig. 8 rather shows something very like spermatozoids ; 

 quere then, may his " resting-spores " be really fertilised spores — 

 true oospores ? That author does not so interpret the matter. He 

 only refers to " swarm-spores " and " resting spores," and does 

 not infer any analogy with Vaucheria. If fig. 8 show really 

 spermatozoids, they escape by the bursting of the parent cell 

 (which would then be an " antheridium") at the summit, not by 

 i ravelling round to meet the resting-spores in a common cavity ; 

 lor they are separate cells (possible " oogonia"). The paper 



