550 



Heritable Spiral Torsions. 



be regarded as intermediate races. The first is Dianthns 

 barhatus tarsus. I obtained a fine twisted branch of this 

 form in the autumn of 1894 from Mr. J. Ensink in 

 Ruurlo. The torsion was simihu* to that represented in 

 Fig. 129, but the fruits were ripe and fuU of seed. I 



coidd not, howex'er, sow the 

 seed until the spring of 1897. 

 This species does not 

 flower till the second year, 

 10-20 shoots being prodticed 

 on each individual. I made 

 a culture of about 300 indi- 

 viduals, which were planted 

 out at distances of 20 centi- 

 meters apart. Plants began 

 to flower in June of the sec- 

 ond year (1898) ; the great 

 majority of their stems were 

 normall}' decussate ; wdiilst 

 several had ternary whorls 

 along the whole length, or in 

 other cases, only in the up- 

 per parts of the stems. Oth- 

 ers again were twisted and 

 manifested a spiral arrange- 

 ment of the leaves. The 

 twisting, too, seemed to pre- 

 fer the upper half of the 

 stem, just underneath the inflorescence. Sometimes how- 

 ever the whole stem, or a great part of it, w^as twisted 

 or the torsion extended into the inflorescence. The maxi- 

 mum development of tlie anomaly largely corresponded, 

 so far as I could determine, with the period of maximum 



Fig 



129. Diatithus barbafus 

 torsus. Twisted Sweet Wil- 

 liam The stem has a de- 

 cussate arrangement of leayes 

 below and spiral above. June 

 1900. 



