562 Heritable Spiral '/'orsions. 
it. For this reason I allowed plants with a right-hand 
spiral only to flower in the seventh generation ; and in the 
following one also, the spiral of all the chosen seed- 
parents was right-handed. The result was as follows : 
LEAF-SPIRAL 
RIGHT-HAND LEFT-HAND 
8th generation 205 215 individuals 
9th generation 40 24 individuals 
These constant but eversporting twisted varieties offer 
favorable material for attempting to transfer the mal- 
formation to related species by means of hybridization. 
At present, however, only a single attempt of this kind 
lias been made, viz., one which was communicated to me 
by Prof. LE MONNIER of Nancy. 1 . 
He sent me two twisted stems of Dipsacus fullonum 
which exhibited a torsion as pronounced and as complete 
as the best instances of my race (Fig. 123 a and b, p. 
529) ; and which owed this malformation to a cross be- 
tween the species in question and my Dipsacus syk'cstris 
torsus, which Mr. LE MONNIER had cultivated on a large 
scale for many years. 
In 1896 my race flowered at the same time as the 
normal D. fullonum in the botanical garden at Nancy, 
at a distance of 100 meters apart but in great quantities 
of individuals. Pollen could easily be transferred by 
insects from one bed to the other. From the seeds of 
these Dipsacus -fullonum there arose besides numerous 
normal plants three with twisted stems ; one of them 
had upwardly directed bracts in the involucre, a char- 
acter of D. syhcstris which distinguishes it from D. ful- 
lonuin. The investigation of this important question has, 
however, not been continued. 
*Iniirn. Roy. Hortic. Soc., 1900. Vol. XXIV, p. 69. 
