THE Root SYSTEM 31 
late in the season when the roots shorten and produce the so-called 
root pull. This opinion has been strengthened by the fact that 
pot cultures in which the corms were carefully placed in an 
upright position, always show many of the corms tilted and some 
almost inverted after one growing season. 
THE ROOT SYSTEM 
The roots of A. triphyllum seedlings have been briefly described 
by Rennert (22, pp. 46, 47), as being of two forms, a group of two 
or three short, slender primary roots and a group of three secondary 
roots. The latter appear after the primary, have an origin higher 
on the corm, are larger and longer than the primary, and are 
contractile. Both primary and secondary roots are diarch in 
structure. To this the writer would add that in all seedlings 
examined he has found but one primary root, and it is diarch in 
structure. The later roots are either triarch or tetrarch. 
In mature plants Rimbach (24) has reported two groups of 
roots in A. Dracontium, and then adds, “Arisaema triphyllum (L.) 
Torr. resembles perfectly A. Dracontium in the behavior of the 
underground organs” (24, p. 175). According to this author 
there appears at the beginning of the growing season a circle 
of long slender simple roots which extend in a more or less hori- 
zontal direction. Later a second group appears slightly above the 
earlier roots. These are ro- 
bust, long, simple roots 
which grow nearly directly 
downward. They show a 
ER 
ASKAN, 
eo 
à ; LS Si 
marked contraction shortly "r&r ERS 
: = a ea 
after their formation. All a as = 
roots are deciduous, being -i : SETTU? 4 
separated from the corms 
about the time of ripening 
of the fruit. The present 
writer has found a varying EFTS 
thickness of 1-2.5 mm. in S a i ae 
the roots of mature corms Fic. 35. Cross section of a tetrarch 
of A. triplellum, and per- ‘Se thong ery marked but Ime 
haps two gjoups in time 
of origin, although the demarcation between the two is not as 
ThA kS 
J 
