Pritchard: Change of Sex in Hemp 
The use of chemicals was limited to 
the year 1909. To facilitate their 
introduction small holes were cut into 
the pith cavities and afterwards closed 
with paraffin. 
In 1914 no leaves or branches were 
detached but all flowers and flower buds 
were removed from branches and stem. 
The counting of the flowers—a labori- 
ous process—was done by fives and tens 
but this nowise interfered with the 
observance of the staminate and pistil- 
late character of the flowers. 
EXPERIMENTS 
Plants were grown for the investiga- 
tions at Madison, Wis., in 1909, 1912, 
1913 and 1914, but owing to a poor 
stand in 1912 and the writer’s absence 
in 1913 when the treatments should 
have been given, the experiments for 
these two years were not completed. 
Hence, the results are limited to the 
two years’ investigation in 1909 and 
1914. 
As no further opportunity has been 
found to continue the work it seems 
better to publish the results now ob- 
tained than to wait an uncertain period 
for the accumulation of further data. 
In 1909, male and female hemp plants 
were used in approximately equal num- 
bers. As each plant had at the time of 
operation already borne a large number 
of exclusively staminate or exclusively 
pistillate flowers, any degree of visible 
327 
monoeciousness could easily have been 
detected. 
The 263 plants treated were mutilated 
by removing their flowers and flower 
buds, their leaves, and varying pro- 
portions of their stems; the tops of 
twenty were also bagged; and the stems 
of sixty others injected with 1 to 2 
ounces of one or more of the following 
chemical solutions: calcium nitrate 
1/10%; zinc sulphate 1/10%; dextrose 
5%; maltose 5%; peptone 1%; aspara- 
gin 446%; potassium iodide 3%; pyridin 
95° formic acid 16000: acetic acid 60” 
n : Be 
30° sodium hydrate 300” 100” 60° 
Alteration of sex occurred under 
several different treatments. Either 
covering the top with a Manila bag or 
injecting into the stem a solution of 
dextrose, maltose, glucose, asparagin 
or pyridin was accompanied by a modi- 
fication of sex. In each instance, how- 
ever, the removal of parts constituted 
a part of the treatment. In fact the 
removal of parts was the only factor 
common to all the sex-developing re- 
sponses. Hence it was probably the 
chief cause of sex alteration. 
Of the 163 plants which reproduced 
flowers after treatment twenty-nine 
or 17.8% developed some flowers of the 
opposite sex. Four of these plants were 
males, the other twenty-five females. 
TABLE I.—Proportion of Monoecious to Dioecious Hemp Plants Found on Successive Dates at 
Madison, Wis., in 1909 
{ 
Number of 
dioecious plants ep pesneeuies 
B z oO O yaar 
Date of examination Imonoecious monoecious Field 
Male Female plants | plants | 
MEPLEHMER 2Ore : 5. A Mee are aera k tase 49 43 8 8.0 A 
SEs 21000 ef A oes ae ace ena ta 96 99 5 pa B 
Pep.cembercGOknaw emcees em eee eee: 0! 174 26 6.5(13.0) | A 
DIGROBEE berths Sulit... Wao eect ae 0 (= 187 13 3: 25(6.5): |B 
MORAL OR te Mus hn ta eae se ca R tects sain ct Nest hapa 0 84 16 8.0(16.0)?) B 
Oetober a secure cyte. se ak tot eer 0 47 3 3.0(6.0) B 
*As no male plants under these conditions formed perfect flowers, the omission of male 
plants in the counting records from September 30 to October 18 gives the percentage of monoeci- 
ousness for only the female type. 
The true percentages of monoeciousness are one-half the 
values inclosed in parentheses as represented by the figures at their left. 
2 Late maturing plants. 
