Cockerell: The Marking Factor in Sunflowers 



545 



These hybrids show the chestnut red 

 color on the basal part of the rays, 

 usually covering less than half of the 

 ray (Fig. D). The general effect is 

 quite different from that of H. annuus 

 var. hicolor. A full description of one 

 of the best of these hybrids is given in 

 Standard Cyclop. Horticulture, Vol. Ill, 

 page 1446. 



This year we have obtained a very 

 interesting hybrid, which may be called 

 X evanescens. It is derived from a 

 vinous H. annuus (v. vinosus) X a 

 very pale H. cucumerifolius . The red 

 color, therefore, comes from the annuus 

 side. The disc is dark, and the rays 

 vary from clear bright lemon (not 

 orange) to pale primrose. When the 

 flowers first open, the basal third or 

 more of the rays is suffused with the 

 anthocyan color, which in the lemon 

 rays is a clear chestnut, often very 

 bright and conspicuous. With time, 

 this red color fades out completely, 

 leaving in its place an orange suffusion. 

 The appearance of the lemon-rayed 

 variety from primrose or cream ancestry 

 appears to confirm the suggestion made 

 in a footnote in Science, August 21, 1914, 

 to the effect that "the pigment of the 

 primrose variet}^ is quite the same as 

 that of the lemon one, appearing paler 

 only because not massed." The factor 

 for density of pigment is apparently 

 independent of that which controls the 



kind of pigment. The loss of the red 

 color with maturity can be understood 

 on the supposition that a deoxidising 

 factor or substance (as described by 

 Miss Wheldale) develops. 



In the dahlia we find another series of 

 color patterns, more or less like those of 

 the sunflower, and similarly independent 

 of the kind of color, whether scarlet or 

 yellow, or vinous or white (compare the 

 colored plates in Gardeners' Chronicle, 

 March 14 and May 23, 1914). I figure, 

 for comparison, a dahlia ray (Fig. I) in 

 which the basal third or less is light 

 yellow, and the rest vinous, reversing 

 the condition of the Helianthus cu- 

 cumerifolius X annuus hybrid. 



Thus it appears that plants may 

 contain determiners, or whatever we 

 please to call them, which produce 

 practically no visible effect in the 

 normal forms, but which give rise to a 

 complex series of effects as soon as 

 anthocyan pigments appear in the rays. 

 We are warned by such phenomena as 

 these that our breeding experiments 

 cannot always ( ? ever) be really 

 restricted to a chosen set of characters; 

 that other characters lie in wait, as it 

 were, to confuse us and trip us up. In 

 other words, the internal environment 

 of the character studied cannot long be 

 neglected, difficult as it may be to 

 understand or to control. 



Inheritance of Sex in Strawberries 



Many thousand strawberry seedlings have been grown at the New York (Geneva) 

 Experiment Station, including some 3,000 selfed plants which have come mainly 

 from five parents. The problem with this fruit of chief importance to the plant 

 breeder is the inheritance of sex. 



While the main breeding work at this station is with fruit, yet the isolation of 

 pure lines in varieties of peas, beans, cabbage and potatoes is also being carried on. 



For nearly twenty years the general problem of the improvement of plants 

 through bud-selection has been in hand. Originally this work was started with 

 the Rome Beauty apple. It now includes also the Baldwin apple. In order to 

 get results more quickly and to handle a larger number of indiyi duals this problem 

 is now being studied in the greenhouses by means of the English violet. 



