162 
Groom . — On the Functions 
below the upper epidermis is considerably more extensive. 
The tubes end in a very similar manner in E. Cyparissias and 
E. puniceus . 
The arrangement of the tubes in the large leaves of Sap him 
sp. (Figs. 4, 5 > 6), does not differ from the preceding type. 
The sub-epidermal system is very extensive indeed. Fre- 
quently, however, cells of the spongy parenchyma form an 
incomplete sheath round the tubes, as described by Haber- 
landt in some other leaves. In the midrib the tubes run 
close to the vessels or in the cortex. The cortical tubes send 
out branches which run below the epidermis, and spread out 
into the lamina. 
In Manihot utilissima , var. dulcis, the laticiferous tubes 
accompany the vascular bundles of the leaves to a large 
extent. Hence the free isolated portions of the tubes are 
much shorter than in the preceding euphorbiaceous leaves. 
There is no sub-epidermal system of tubes. The most that 
the tubes do, is to push up between the extremely long and 
narrow palisade-cells. 
Conduction of carbohydrates in Euphor biace ae. — The present 
observations on Euphorbia Peplus agree precisely with those 
of Schimper. The carbohydrates appeared to be conducted 
by the nerve-parenchyma just as if there were no laticiferous 
system. An additional experiment was performed with these 
leaves. Leaves poor in starch were separated from the plant. 
They were then left exposed to daylight in a saucer con- 
taining water. The leaves continued to live for days and 
manufactured starch. They were collected in the morning, 
day after day, for five days. A large amount of starch was 
present in the leaves finally. This starch was especially col- 
lected inside or close to the nerve-parenchyma. There was 
no aggregation of starch in the region of the free laticiferous 
tubes, neither was there any appreciable difference in the 
quantity of starch inside the tubes. But this last fact could 
only be observed very incompletely and solely in the free 
tubes (i. e. tubes separate from the bundles), because of the 
large amount of starch present. These facts were the more 
