KNOWLEDGE OF MONOCOTYLEDONOUS SAPROPHYTES. 183 
starehless cells inside the ridge to the elongated conducting paren- 
chyma with starch is sudden, and corresponds with constriction 
of the ridge. At the constriction itself all the cells, including 
the epidermal, have starch, and the starch-containing cells 
on the other side of the bundle here are joined to the outer 
epidermis (Pl. V. fig. 4). The outer half of the tissue con- 
necting the two ridges is devoid of starch, and is constituted of 
the outer epidermis and two layers of large parenchymatous 
-cells. Some of the latter contain raphides and mucilage. These 
histological details suggest that, when the fruit is developing, the 
plastic products carried up by the interplacental bundles are 
rapidly transferred to the placente by the peculiarly developed 
conducting parenchyma-cells, and that even the inner epidermis 
plays the same róle of conduction. 
General Remarks on Aphyllorchis. 
On the whole, histological evidence confirms the view gained 
from the examination of the grosser morphology of Aphyllorchis : 
that is, that the loss of chlorophyll has not been associated 
with any fundamental changes in the structure of the plant. It 
is hence possible that we are dealing with a holosaprophyte which 
has tolerably recently lost its power of assimilating carbonic acid. 
The points in which the plant resembles a typical autotrophic 
plant or a green orchid are: a full development of root-hairs, 
the occurrence of a typical exodermis, normal vascular bundles, 
and stomata. With reference to the occurrence of stomata, 
they do not alone denote that the plant has only recently 
lost its chlorophyll; for stomata occur in the much modified 
holosaprophyte, Epipogum aphyllum, on the rhizome, and still 
more remarkably on the curious holoparasitic Lennoacee. 
The occurrence of well differentiated water-conducting con- 
stituents in the xylem renders it highly probable that there is a 
considerable transpiration-current. Doubtless the widely open 
stomata on the subterranean scale-leaves and those on the aerial 
parts of the shoot enable the plant to get rid of its excess of 
water. The presence of distinct intercellular spaces under these 
stomata does not necessarily imply that the water is sent out 
in a gaseous form, though it may at first seem more probable. 
Clearly, then, in this plant the leaves, as in Galeola, are essentmlly 
the organs of transpiration for the plant ; and, just as in Galeola, 
there is a relative dwindling of the phloém in the bundles of the 
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