PHYSIOLOGICAL OBSERVATIONS ON SOME 
. PERENNIAL HERBS. 
A. RIMBACH. . 
(WITH PLATE XIII) 
I. 
Arisaema Dracontium (L.) Schott.—During winter Arisaema 
Dracontium consists of a stem-tuber, the growing point of which, 
covered by several scale leaves, lies at about 5°™ below the sur- 
face of the earth. It is devoid of roots. Early in April the 
bud begins to elongate upwards, and at the same time from fif- 
teen to thirty roots break out in a ring like zone from the base of 
the bud ( fig. 4). They appear almost simultaneously and grow 
horizontally, radiating in all directions from their point of origin. 
They are 1 to 1.5™" in diameter throughout their entire extent, 
and attain a length of more than 20%. After a time some of 
them become somewhat transversely wrinkled at the base, 
because they undergo there a slight longitudinal contraction. 
At the end of April the scale leaves protrude from the soil. 
They are tightly appressed to each other and enclose a hollow, 
‘n which the foliage leaf develops ( fig. 6). In the latter the 
end leaflet is vertically extended, the lateral leaflets are bent 
Mdieigd and the blades of all are involutely rolled up. After 
“ving reached the surface of the earth, the scale leaves stop 
re Stowth, and at the end of April or beginning of May the 
lage leaves and inflorescences break out from their coverings 
- 4nd unfold in the air. In the course of May the inflorescence 
: ‘ 
seus About the same time a second set of roots is formed 
Mediate] ee 
diffe y above the first one (fig. 5), but there is a striking 
rence between the two. The roots of the second set are 
cker, about 2.5mm 
£Y grow from 
and 
1900 
thi : 
in diameter, and taper towards the end. 
their origin vertically downwards or nearly So, 
ee ©ver into a horizontal direction only at their thin end 
171 
