Febeuaby 17, 1911] 



SCIENCE 



263 



as those on stems cut and placed in water, but 

 under the same conditions of light, temperature 

 and air moisture. In this plant sufficient water 

 to keep the leaves turgid for three to eighteen 

 days will rise through a stem 15-60 cm. high, 

 with a section 5-60 cm. long killed with steam. 

 Experiments show that a certain amount of water 

 is raised through the steamed portions, but that 

 it gradually diminishes in quantity from day to 

 day, until the leaves become air dry. The dim- 

 inished water supply is partly due to a partial 

 blocking of the vessels with a gum-like substance, 

 which probably owes its origin to the disorganiza- 

 tion of the contents of the sieve tubes caused by 

 heating the stems. The withering of the leaves 

 above the steamed portion is probably caused by 

 the action of deleterious substances introduced 

 into them from the dead cells more than from 

 lack of water. The poisonous substances are 

 probably disorganization products caused by 

 steaming the stems. The withering leaves above 

 a steamed portion of the stem show all of the 

 symptoms of dying, namely, rapid loss of water 

 directly after treatment, then a more uniform 

 loss, rounding up and discoloration of the chloro- 

 plasts and contraction of the protoplasts. The 

 leaves apparently die, not so much from lack of 

 water supply, as on account of the death of the 

 cells from other causes. It is evident from ex- 

 periments that the steaming method of killing 

 portions of the stems is not a satisfactory one in 

 order to settle the question of the relation of the 

 living cells to sap-flow. Other methods have been 

 used. Killing a portion of the stem by applying 

 wax heated to 110° C. causes less apparent ais- 

 organization of the cells of the stems, less injury 

 to the leaves above and does not cause a marked 

 immediate decrease in the amount of transpira- 

 tion. 



An Vndesoribed Type of Elodea Floicer: Robert 



Bhadfoed Wylie. 



An unusual (and apparently undescribed) type 

 of staminate flower was collected by the writer 

 from East Okoboji Lake, Iowa, during the sum- 

 mers of 1909 and 1910. In this strain, which 

 occurs abundantly in the locality, the axis of the 

 staminate flower elongates rapidly at maturity, 

 pushes out of the spathe and carries the pollen- 

 bearing flower to the surface of the water, where 

 it opens still attached to the plant. The degree 

 of elongation may be as great as in the pistillate 

 flower. While the general appearance of the two 

 flowers is similar, and the habits of reaching the 

 surface of the water are biologically alike, the 



parts concerned are not homologous. The elon- 

 gated portion of the staminate flower is the axis 

 below the floral parts, while that of the pistillate 

 flower is the complex above the ovary in epigynous 

 flowers called the " floral tube." In the opinion 

 of the writer the form deserves specific rank, and 

 the name Philotria lowensis {Elodea lowensis) is 

 proposed. 



The Flora of a Saline Lake: M. A. Brannon. 



This report is based upon a study of Devil's 

 Lake, situated in Benson and Ramsey counties. 

 North Dakota. It is a saline lake in the lowest 

 portion of an inland drainage basin comprising 

 about 4,000 square miles. The lake has lowered 

 about 14 feet within 27 years with the attendant 

 results of receding shore line, separation of the 

 former lake into divisions and an increase in the 

 salinity of the water. 



Waves and the longitudinal and vertical cur- 

 rents cause thorough and rapid distribution of 

 the phyto-plankton in which representatives of 

 the Myrophyceae predominate. 



Ruppia maritima is the only spermatophyte 

 found in Devil's Lake. It grows in profusion on 

 submerged terraces along shores protected by high 

 land terraces. 



Enteromorpha proUfera, various species of 

 Cladophora, and some of the Protococcales are 

 the only Clorophycese found in this saline lake. 



A study of ecological factors has been conducted 

 with reference to pulsation in plant multiplica- 

 tion and in connection with inhibition of plants 

 growing in adjacent bodies of sweet water. 



Nodularia spumigens var. litoria gave the fol- 

 lowing record: May 29, 1910, there were three to 

 five per cubic centimeter, August 18 there were 

 several hundred filaments per cubic centimeter 

 and on November 1 only two to three per cubic 

 centimeter. 



This pulsation was believed to be caused largely 

 by the increased heat. The temperature readings 

 on May 29 were 14° C, August 18 20° C. and 

 November 1 11° C. The maximum portion of 

 the curve was coincident with increased light 

 action and increased wave and current action of 

 the lake. 



Spirogyra and Ohara were used in the inhibition 

 experiments and the results indicate that loss of 

 turgidity when immersed in saline solutions was 

 largely responsible for the non-existence of these 

 and other forms in Devil's Lake. Enteromorpha 

 and Cladophora are capable of standing ten to 

 thirteen per cent, salt solutions, according to 

 Oltmanns, hence these forms are not inhibited 



