469 
Anatomy of Teratological Seedlings. IV. 
41). It will be noted that in no instance does the root-whorl consist of 
five members, although one ‘ Type 1 ’ specimen was obtained which, on 
macroscopic evidence, was thought to provide evidence of such a condition. 
In this seedling the hypocotyl is symmetrically triarch (Fig. 44), and 
a lateral root arises from each of the three poles (Fig. 45, a, b , c). Two 
additional roots (Fig. 45, adv, adv 1 ) arise at the same level which are not 
referable to any protoxylem, and sections at a lower level show that the main 
root has been broken off and is replaced by a healed stump, on either side of 
which are two heptarch adventitious roots (Fig. 46). The two lateral roots 
arising at the level of the root-whorl are evidently adventitious also, and 
conform to the description given by Miss McClatchie ( 23 ), who has shown 
that the production of adventitious roots of this type at or near the surface 
adv 1 
<Figs. 43-46. A ‘Type 1 ’ seedling in which the tap-root has been destroyed. Note the 
adventitious roots, adv., adv. 1 , at the base of the hypocotyl, and the two heptarch ones arising to 
either side of the healed stump at a lower level. 
of the soil is a characteristic traumatic response in Impatiens Roy lei. The 
results with regard to the derivation of the root-poles may be summarized 
as follows : 
‘ Type 1 1 Seedlings. 1 Type 2 ’ Seedlings. 
{a) One additional pole arising de novo in the 
hypocotyl or tap-root 
lb) One additional pole arising by the per- 
sistence of an independent lateral 
. (c) Two additional poles by the combination 
of ( a ) and ( b ) 
( a ) Two additional poles arising de novo in 
the hypocotyl or tap-root 
( e ) Two additional poles arising by the per- 
sistence of both independent laterals 
If) One new pole arising by the bifurcation 
of the protoxylem 
Common 
Fairly common 
Very rare. 
Very rare 
Unknown 
Very rare 
Somewhat rare 
Fairly common 
Common 
Common 
Very rare 
Unknown 
It is obvious that a series of modifications so suggestively similar in the 
two types of seedling points to community of origin, especially when, as is 
the case here, extremely intimate syncotyly leads to the type of modification 
found commonly in ; Type 2 ’ seedlings. We can thus say that points of 
