II4 BOTANICAL GAZETTE | AUGUST 
3:25:5 P.M. Indicator bubble at roo™*. Temp. 21.5°C. 
ac4n7§ * ‘ 200 a Se 
Readjusted. 
Ss : 41 “ce sé ‘cc “ fe) “ 20.8 
ifs 58 “ 6“ 6c ce 500 “ 19.2 eS 
Net duration of experiment, 8 hours and 38 minutes; total amount 
of water used, 3.7 grams. The irregular variations in the forenoon 
were due to gusts of wind and the repeated opening of the doors. 
The leaves showed a superficial extension of 300 “! ™, including 
the petioles; area of stem surfaces, 40°. April 16 the leaves were 
stripped from the shoot, the base of which was trimmed and refitted to 
the apparatus, and the following observations were made: 
10:31 A.M. Indicator bubble at o™%. Tem. 17.5° C. 
EY ) eo 2a0 
II: 43 “ce ““ “ * 200 “ 18.8 
12713 PM: re = * 300 sis ye 
I 223 “ “ “c “ 500 “6 16.0 
2:00 “e “ec “ce < 600 ‘sé 15.1 
The data given above demonstrate the value and accuracy of this 
method of observation. 
Valuable data of the transpiration of winter branches and buds, 
and opening leaf and flower buds have also been obtained by the use 
of this instrument. 
The apparatus was constructed and calibrated by the mechanics 
whose services are available to the department.—D. T. MacDouGat, 
University of Minnesota. 
PARTHENOGENESIS IN MARSILIA. 
In February 1896 the writer was led to suspect that some prothallia 
of Marstlia Drummondiit which had been grown in the laboratory had 
developed embryos of considerable size without fertilization having 
been accomplished in every case. In order to determine whether this 
was possible, and if so to what size the sporophytes would develop, 
macrospores were isolated from the microspores before the antheridia 
matured. Spores were sown on February 13 and February 20. At 
each time two sporocarps were used. Each was cut on one side to 
admit water more rapidly, and placed in distilled water in a separate 
dish. In an hour or two all the sporangia were expelled from the 
oes 
— 
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PEs ye 
