530 Wisconsin Academy of Sciences , Arts, and Letters. 
upper ends of the cells by the formation of a protrusion. This 
is then cut off and forms the first cell of the branch. 
Reproduction takes place either sexually or asexually. Asexual 
reproduction is by means of biciliate zoospores which arise in num¬ 
bers from the upper cells of the filaments and escape from these 
sporangia by a lateral opening in the cell wall. Sexual repro¬ 
duction is isogamous. Sexual swarm cells or planogametes are 
formed by the division of cells in a manner similar to that of the 
formation of zoospores, but in much greater numbers. By con¬ 
jugation of planogametes in pairs, zygotes are produced which, 
after drawing in their cilia, become spherical and then surrounded 
by a thick cell wall. After a period of rest, each zygote gives rise 
to several swarm spores. These swarm spores develop into new 
filaments. 
Myriophyllum is more abundant than Cladophora. A quan¬ 
titative survey of the flora of this lake by Rickett 2 shows that 
Lake Mendota contains, when calculated by weight of the fresh 
plant, about eleven times as much Myriophyllum as Cladophora. 
This Myriophyllum is a perennial aquatic plant which supports 
a vertical portion of the stem considerably above the water sur¬ 
face, and on the emersed portion ordinary aerial leaves are 
borne. The submerged leaves are finely cut. The leaves are 
often crowded and sometimes whorled. The flowers are borne 
usually above water in summer. 
The methods of analysis used for both the organic and the in¬ 
organic plant constituents were, in the main, those of the Associa¬ 
tion of Official Agricultural Chemists 3 . Inasmuch as these are 
recognized and standard methods, no description will be given of 
them. All results are calculated on an air-dry basis. 
2 See the preceding- paper, Note XVII. 
3 U. S. Dept. Agr. Bur. of Chem. Bull 107 (revised): 21-24; 38-39. 1912. 
