352 



The Journal of Heredity 



FINE DOWN AND STINGING HHISTLES 



This is a portion of Fig. 8, magnified. The fine down of the Cliina bean on the left is to be com- 

 pared with the stinging bristles of the Fl Velvet x Cliina hybrid on the right. vScale in 

 millimeters. (Fig. 10.) 



shown in Fijj^. 8a. I am unable to 

 distinguish the bristles from the three 

 hybrids, even with the microscope. 

 They arc photographed, toj^ethcr with 

 one from 5. priiritiim, in Fi}^. 14. 

 These bristles are about one and a half 

 millimeters long. The bristles of the 

 first generation hybrids are shorter and 

 thinner than those of 5. pniritum and 

 have less gum in the tip. They also 

 sting less. A part of a pod from a first- 

 generation plant of the Velvet by China 

 cross is depicted on the right of Fig. 10. 

 One of the bristles from this ])od is 

 photographed on the left of Fig. 15, its 

 tip is shown on the right of Fig. 14, and 

 a number of bristles are shown in Fig. 

 13. When, after the first frost in the 

 fall, young stinging pods dry uj), their 

 pubescence becomes l;)lack, flattened, 



and more or less twisted, much like that 

 of the Velvet bean. 



THE SECOND GENERATION 



The chief t>'pes of plant-hair appear- 

 ing in the second generation are shown 

 in Fig. 15. They are: 



(1) stinging bristles, about one and 

 a half millimeters, or more; 



(2) fine down, about half a millimeter; 



(3) coarse down, up to about three- 

 quarters of a millimeter; 



(4) intermediate between downy and 

 stinging, alxmt one millimeter (not 

 shown) ; 



(5) long tomentum over one milli- 

 meter long, like that of the Velvet bean, 

 with a ])atch of black tomentum on the 

 calyx, but white ]nibcsccncc on the rest 

 of the plant; 



