356 



The Journal of Heredity 



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TIPS OF STINGING BRISTLES 



Tlie first is from the wild S. pruritum, and 

 contains much K^^irn in the i)C)int. The 

 second, thirdand fourtharefrom Fl plants 

 of Lyon x Velvet, Velvet x Yokohama and 

 Velvet X China, respectively. They are 

 indistinguishable, and contain less gum. 

 Scale in tenths and hundredths of a 

 millimeter. (Fig. 14.) 



From one of these smooth black 

 plants, a constant seedling family was 

 raised in F5. 



Hence the sej^rej^ation of the jjroj^eny 

 of heterozygous downy plants is, 



Downy. 

 3 



Smooth Black. 

 1 



Figs. 16 and 17 show respectively 

 downy and smooth black jjlants of the 

 fourth generation. A pod of one of 

 these smooth black ])lants is shown in 

 Fig. Hd. The ])ods of these i)articular 

 downy i;lants were not unlike the China 

 pod shown in Fig. (S/). 



"VELVET" PLANTS.— Out of five 

 families, three were constant "Velvet," 

 and two segregated into, 



The recessive downy plants have long 

 appressed silky down (up to one milli- 

 meter) on their pods, and a patch of 

 black tomentum on the calyx like the 

 "Velvet" plants. 



From a " Velvet " plant of one of these 

 families, two families were raised in F4 

 and F5, which segregated into. 



"V^elvct." 



(Calculated 32 



Recessive Downy. 

 10 

 11) 



From one F4 recessive downy plant, 

 a constant family was grown in F5. 



Hence the segregation of the progeny 

 of heterozj^gous "Velvet" plants is, 



"Velvet." 

 3 



Recessive Downy. 

 1 



LONG BLACK PLANTS.— Only 

 three families were grown in the third 

 generation. Their parents were se- 

 lected for maximum crop. One F2 

 parent with weak tomentum gave in 

 F3, 



Long Black. Smooth Black. 



35 : 15 



(Calculated 37.5 : 12.5) 



Two F2 parents with stiflfcr tomen- 

 tum gave in F3, 



From one of these last families, several 

 families were grown in F4 and F5. IMost 

 of the long black segregated, but some 

 were constant. The "W^lvel" were 

 constant. 



Hence the ])rogeny of some of the F2 

 long black plants segregates into, 



Long Black. 

 3 



Smooth Black. 

 1 



Others segregate into, 



Long Black. 

 3 



"Velvet." 

 1 



Most of the F2 lonj 

 yield very poor crops. 



black i)lants 



