642 



SCIENCE 



[N. S. Vob. LII. No. 1357 



Almost one half of the total yield is found 

 in water from 1 m. to 3 m. in depth. More 

 than one quarter is found in water shallower 

 than this, and a quarter in deeper water (3 m. 

 to 7 m.). 



Almost one half of the wet weight of the 

 total yield is made up of Vallisneria spiralis. 

 The dry weight of this plant forms a some- 

 what smaller fraction of the whole, owing to 

 its relatively high water content. The re- 

 mainder of the vegetation is composed mainly 

 of various species of Potamogeton. P. ampli- 

 folius composes ahout one quarter of the total, 

 P. pectinaius and P. Bichardsonii each about 

 one tenth. ISfone of the remaining species ex- 

 ceeds 4 per cent, of the total. 



The above is an average for the whole 

 plant zone. At different depths the situation 

 varies. Potamogeton pectinatus, P. Bichard- 

 sonii, and other species, including Najas 

 fiexilis, Banunculus aquaiilis. and Chara 

 crispa, bulk large in water less than 1 m. in 

 depth. Between the depths of 1 m. and 3 m., 

 Potamogeton amplifolius replaces to a large 

 extent the other species of this genus, and 

 Myriophyllum and Oeraiophyllum are abun- 

 dant. In the deepest water (3 m. to 7 m.), 

 P. amplifolius composes about one half of the 

 entire vegetation. Vallisneria forms a large 

 part of the growth at all depths. 



The greater the depth, the smaller is the 

 number of species. Many plants are re- 

 stricted to the shallow water. Among these 

 are Banunculus and the rare species Pota- 

 mogeton lucens. On the other hand, most of 

 the Potamogeton zosterifolius is found in 

 water deeper than 3 m., and about three 

 quarters of the Myriophyllum and Cerato- 

 phyllum is found in water from 1 m. to 3 m. 



Within each depth-zone, the abundance of 

 the vegetation is different in different stations. 

 The figures obtained represent, therefore, 

 averages of widely varying conditions. Much 

 of this difference is correlated with the char- 

 acter of the lake bottom. Especially in the 

 shallowest water, there are large tracts of 

 sandy bottom, on which Potamogeton pectina- 

 tus, P. Bichardsonii, Banunculus, Najas, and 

 Chara thrive, while other species do better in 



muddy regions. Vallisneria flourishes equally 

 on mud or on sand. Both the character of 

 the bottom and the nature of the flora are 

 more uniform in the deeper water. 



In addition to the plant zone as a whole, 

 there are a large number of shallow bays 

 which have distinctive flora. Here grow a 

 number of marsh and pond plants not found 

 elsewhere in the lake, including Scirpus 

 lacustris, Castalia odoraia, Nymphaea advena, 

 Typha latifolia, and other less common species 

 Almost all the other species found in the lake 

 are also present in the shallow bays. Here 

 also the character of the vegetation varies 

 considerably with the nature of the bottom. 

 Quantitative determinations of this class of 

 cases were very difficult to make, owing to the 

 irregular, patchy nature of the growth, espe- 

 cially in the case of the larger marsh plants. 



Around the margin of the lake extends a 

 narrow strip of Cladophora glomerata, grow- 

 ing attached to rocks of various sizes. This 

 plant varies greatly at different points in the 

 density of its growth. Samples were collected 

 from representative spots, field notes taken on 

 the general distribution and abundance of the 

 species, and an estimate of the total made 

 on the basis of these data. 



A detailed report of these investigations is 

 to be published in the Transactions of the 

 Wisconsin Academy of Sciences, Arts, and 

 Letters. 



H. W. ElCKETT 



Department op Botany, 

 TjNrvERSiTY OP Wisconsin 



THE AMERICAN CHEMICAL SOCIETY 



( Continued) 



DIVISION OP DTE CHEMISTRY 



A. B. Davis, chairman. 



E. Norris Shreve, secretary. 



Wednesday and Thursday 



Physiology Lecture Eoom 



New naphthalene dyes: A. S. Wheeler. The 



tones produced vary with the reaction of the 



bath and also may be modified considerably by 



the use of mordants. The sulfonation of naptha- 



lene with fuming sulphuric acid, is carried out at 



a low temperature and is so regulated that the 



