Studies of Teratological Phenomena. 



103 



5. Fasciation and hybridization. 



The hybridization work with the fasciated race was the most 

 important part of the investigation. Crosses between it and various 

 normal species and varieties have been numerous, and one such hybrid 

 family has been grown to the F4 generation. Crosses were also made 

 between it and a calycanthemous- flowered race, N. t. calyciflora. The 

 Fl progeny will all be described together; the later generations of all 

 crosses, under their respective headings. All parents used in this 

 hybridization work are typical plants of the forms described under 

 materials. Where the individual record of any fasciated parent used is 

 known, it may be found in Table 9. The number, place and year in 

 which any cross was grown is given in Table 7. The factor for fasciation 

 is designated (A), that of calycanthemy (B). 



a) Fasciation X Normal. 



Fj progeny (Fig. 16 u. 17). 



Eight successful species and varietal crosses were made with the 

 fasciated race. The species hybrids were all sterile, while the varietal 

 Fl hybrids were all fertile. The 

 species cross (331 X 301) was not 

 grown in sufficient numbers to give 

 valuable data. The others, though 

 sterile, gave important data regar- 

 ding the nature of dominance. 

 Tables 6 — 12 give the frequency 

 distribution of floral parts (sepals, 

 petals, etc.) per flower per indivi- 

 dual plant of each different hybrid 

 family. Table 13 shows the frequency 

 distribution of parts per flower for 

 the .family as a whole, and gives 

 the mode, number of flowers and 

 plants examined and the character 

 of single average flower for each 

 of the crosses. 



Exceptions to uniformity in Fi. All the Fi plants of a given 

 cross and its reciprocal were alike in the characters under observation 

 with two exceptions. One of these was probably a reversal of dominance 



Fig. 16. Expression of calycanthemy (B) 



in Fj flowers from 396 ;< 342. Note 



the petaloid sepals. 



