564 



The Journal of Heredity 



be jnit in class lb, but so far its effect 

 in bays and blacks has not been worked 

 out. 



COLOR I.NHI-RITANCE IX HORSK HYBRIDS 



There are a number of curious facts 

 in connection with horse hybrids which 

 need more investigation. Gray and 

 piebald remain dominant in crosses be- 

 tween horses and asses. In a cross made 

 by Ewart''' between a zebra and pie- 

 bald mare the hybrid showed no trace 

 of the i)iebald pattern, but the dam may 

 have been a heterozyj^ous piebald. It is 

 often held that dun is the ancestral 

 color of the horse, the wild Przcvalski 



horse showinj^ an approach to this color. 

 Zebras also show a pale cream ground 

 color with black stripes and would 

 be expected to have factor D. Never- 

 theless, when crossed with chestnut, 

 black, or bay horses, the offspring ap- 

 I)roach bay rather than dun. If the 

 zebras contain the same factor as dun 

 horses, dominance is reversed. Finally, 

 another apparent reversal of domi- 

 nance must apparently take place in 

 the production of chestnut mules, as 

 anything like this color is unknown in 

 donkeys and factor b is recessive in 

 horses. 



The Occurrence of Seven-Leaved Clover Leaves 



Apropos of De Vries' achievement in 

 producing a seven-leaved clover by 

 breeding from a four-leaved strain, 

 sometimes cited as i)roof of the cumula- 

 tive effect of selection, I wish to say 

 that I at one time found in the field a 

 l)lant which closely resembled De Vries' 

 jjroduction, it having one leaf with seven 

 leaflets, one with six, a goodly number of 

 fives, and the remainder nearly all four- 

 leaved. There were onl\' a few normal 

 leaves on the plant. 



This would seem to place De Vries' 

 achie\-ement on a i)ar with that of 

 LuthcT Hurbank in producing a scarlet 

 California jjojipy from a yellow one hav- 

 ing a red strii)e. According to W. J. 

 Si)illman, such scarlet i)0])pies have 



been found growing wild, and Burbank's 

 achievement might therefore be as- 

 cribed to the untangling of hereditary 

 characters already in existence. 



As this clover ]:)lant of which I sjieak 

 was found in late autumn and had 

 disapi^eared the following spring, no 

 seed could be saved, and as my speci- 

 mens were not preserved with sufficient 

 care I now have nothing to show for it 

 but an o])inion that if the matter were 

 made the subject of sufficiently wide 

 in(iuir\-, other such ])lants would be 

 brought to light, this discovery being 

 rendered probal)le by reason of the i)op- 

 ular interest taken in four-leaved clovers. 

 II. D. Tknnent. 

 .MeConnelsville, Ohio. 



'* liwart, j. C. ISOQ. '\'hv Penyoiik E.xperiments. 



