XENIA AND THE ENDOSPERM OF ANGIOSPERMS 
E. M. EAst 
As is well known, the term “‘xenia”’ was proposed by FockeE to 
describe any effect of pollen of another race upon the tissue of a 
seed plant apart from that initiating the formation of an embryo. 
As it has been exceedingly questionable whether any such effect 
beyond a chemical irritation ever occurs, the word has come to be 
applied to the appearance of the F, hybrid endosperm produced by 
the fusion of the second male nucleus with the so-called endosperm 
nucleus of the embryo sac, when its characters are different from 
those exhibited by the mother plant after self-fertilization. 
Since the fact of this fusion was proved cytologically by Guic- 
NARD (10) and NAWASCHIN (11), data on this type of xenia have 
interested botanists because of the differences of opinion existing 
concerning the phylogenetic significance of the angiosperm endo- 
sperm. 
The most detailed observations on xenia have been those on 
maize, since numerous maize varieties exist with differences in 
endosperm characters. The behavior of the following factors in 
heredity is known from the researches of DEVRIES (5), CORRENS 
(2), WEBBER (12), East and Haves (7), and Emerson (9). In 
addition, East (6) has found good indications of at least three 
additional factors that modify the expression of the red and the 
purple aleurone colors. 






Factor Action 
\ APE rear aire Causing full development of starch grains 
Fe ae ausing yellow color throughout endosperm 
L SOR ie ORE te Similar to Y, but not allelomorphic to i 
Ce ia ee ..| Basic color factor necessary for color in aleurone cells 
Be al, Present wi ed color in aleuron 
Pies ee Present with R and C gives purple color in aleurone cells 
ee Se Inhibits aleurone color when present with RC or PRC 


Observations on crosses wherein these characters have been 
concerned have made it possible to formulate the following law 
regarding xenia: 
217] [Botanical Gazette, vol. 56 
