82 
Variability in Stellaria Graminea. 
respectively. Individuals of both kinds it will be remembered, set 
good seed and hence have probably been pollinated. The herma¬ 
phrodite individuals cross-pollinate among themselves since the 
flowers cannot, of course, receive pollen from male-steriles. The 
male-steriles, on the other hand, if pollinated, receive pollen from 
hermaphrodite individuals and hence the conditions obtain for 
Mendelian hybridization. These plants might produce apogamous 
offspring as in the male-sterile hybrid CEnotheras described by 
Gates 1 ; but in GEnothera the apogamously produced forms appear 
to be of rare occurrence. 
De Vries 2 in the cross 0. lata (female) X O. Lamarckiana 
(hermaphrodite) found hermaphroditism dominant and obtained 
segregation into lata and Lamarckiana forms in the F 2 generation, 
but Gates, 3 later, did not obtain complete segregation of the parenta 
characters in this cross. Salaman, 4 on the other hand, finds male- 
sterility in Potato a dominant character. The cross Record (female) 
X Flourball (hermaphrodite) produced all sterile plants in F^ and 
in F 2 , forms with pollen present and pollen absent. It is noteworthy 
that the forms possessing pollen can be arranged in classes according 
to their richness or poorness in pollen—the quality of the recessive 
parent being not fully reproduced. Two plants of the Fj generation 
obtained from the cross Congo (female) X Flourball (hermaphrodite) 
were selfed and forty-four plants were obtained. Of these, three 
with normal anthers contained no pollen; four, a little; two, 
medium quantities and thirty-five abundant pollen. Since different 
results have been obtained by different investigators working with 
different genera, it is unwise to predict the result of the cross 
female X hermaphrodite in the case of S. graminea. The individuals 
of the intermediate series referred to above, however, may prove to 
be hybrid forms obtained in the F 2 generation and 1 am arranging 
to test the matter experimentally. 
The experiments described in this paper have been carried out 
with the kind assistance of Mr. C. C. Titchmarsh of the R.H.S. 
School of Horticulture. 
1 R. R. Gates. Science, N.S. XXX, No. 776, p. 691 (1909). 
2 H. de Vries. Die Mutationstheorie, Vol. I, p. 168 (1901-1903). 
* R. R. Gates. “ Pollen Development in Hybrids of CEnothera lata x 0. 
Lamarckiana." Bot. Gaz., 43, p. 83 (1907). 
4 Redcliffe N. Salaman. “ Male Sterility in Potatoes, a dominant 
Mendelian Character,” Journ. Linn, Soc. Bot., XXXIX, p. 301 (1910), 
