Malloch: Sex Inheritance in Hemp 



28 



midribs which results in excess leaf 

 surface thus causing a folded and wavy 

 appearance of the leaf. 



The writer discovered a leaf and 

 stem chimera in a male plant belonging 

 to the variety Tochigi. The stem of 

 hemp is four-angled with four distinct 

 ribs. The lower leaves are opposite, a 

 leaf arising from opposite ribs. On 

 the particular plant under observa- 

 tion one of the four ribs was divided 

 with a distinct depression between the 

 divided strands for a distance includ- 

 ing five series of leaves. The mutation 

 arose in an intervening rib between 

 two opposite leaves and ended in the 

 same fashion (See Fig. 21). One-half 

 of the divided rib was normal green 

 while the other half was near "Martins 

 Yellow."^ Whenever a leaf arose from 

 this divided rib, one half of the leaf 

 and petiole was normal green, while 

 the other half was "Martins Yellow." 

 As hemp usually has an odd number of 

 leaflets the middle leaflet was half 

 green and half "Martins Yellow." 

 The flowers arising on the normal side 

 were of the normal type, while those 

 arising on the abnormal side were 

 "Martius Yellow" in color. The 

 yellow flowers failed to open in this 

 particular instance but were normal 

 in all other respects. 



This is clearly a sectorial chimera 

 and further illustrates the possibility 

 of obtaining new characters in hemp. 

 Cannabis also exhibits differences in 

 size characters and in seed coat shades. 



Pritchard^ and Schaffner^° have 

 shown that there is considerable varia- 

 tion in the sexual expression of hemp 

 under certain environmental condi- 

 tions. Pritchard obtained reversal of 

 sex on both male and female plants by 

 the removal of a certain number of 



flowers. Pritchard supports the hy- 

 potheses of Darwin and Strassburger in 

 that both males and females are sup- 

 posed to be potential hermaphrodites. 



Schaffner observed teratological flow- 

 ers and complete sexual reversal when 

 the plants were grown on shallow 

 benches in the greenhouse with low 

 light intensity. This phenomenon was 

 not found in my cultures due perhaps 

 to better environmental conditions. 

 Schaffner states that "sexuality is a 

 state or condition not Mendelian 

 in nature, but related to the functional 

 activity of the plant and profoundly 

 influenced by the environment." The 

 statement is also made that "the 

 ratio between carpellate and staminate 

 individuals is about 1 : 1 with a 

 large deviation in either direction for 

 various plots." The equality of sexes 

 was also found by the writer in the 

 present observation. Unless some other 

 plausible hypothesis can be offered 

 to explain the equality of sexes, we are 

 justified in accepting the Mendelian 

 theory as the most probable basis for 

 this phenomenon. The factor of nu- 

 trition can hardly furnish a mechanism 

 for the equal distribution of sexes 

 under normal environmental condi- 

 tions. 



The reversal of sex in hemp is an 

 extremely interesting and important 

 observation and it calls to mind the 

 cases of the abnormal abdomen in 

 Drosophila and the red flowered Pri- 

 mula. The cytologist has yet to 

 determine what the germinal basis is 

 for the sexual dimorphism exhibited 

 by hemp and it remains for the 

 geneticist to establish the genetic 

 nature of this extreme range of charac- 

 ter expression. 



' RiDGWAY, R. Color Standards and Nomenclature. Published by the author, Washington, 

 D. C. 1912. 



^Pritchard, F. J. Change of Sex in Hemp. Journal of Heredity VII: 325-329. 1916. 



'"Schaffner, J. H. Influence of Environment on Sexual Expression in Hemp. Botanical 

 Gazette ^V\\: 191-219. 1921. 



