KNOWLEDGE OF MONOCOTYLEDONOUS SAPROPHYTES. 205 
strengthened on remembering the habitat of the plant. I found 
hundreds of individuals dotting the hill-sides on Dane’s Island, 
Whampoa; all of them grew in black humous soil. Still there 
is a large leaf-surface, so I thought it might be worth exami- 
nation. 
Roots. 
The roots are tolerably succulent. Outside is a persistent 
piliferous layer of one layer of cells, the outer walls of which are 
feebly cuticularized. The walls are marked with reticulate 
cellulose-thickenings which run in a direction at right angles to 
the axis of the root. Some of the cells grow out into very long 
slender root-hairs. Mycorhizal hyphe penetrate by means of 
these hairs, and by them alone. Within is a typical exodermis 
with thin suberized walls and passage-cells. It is succeeded by 
about ten layers of cortical parenchyma, in some of the outer 
layers of which mycelia occur. Starch was found in all the cells 
excepting those infected with mycorhizal hyphz, and excepting 
the raphide-mucilage cells. A thin-walled endodermis and 
a polyarch stele with an interrupted pericycle complete the 
structure. 
Scape. 
The scape is long and slender, and has only small bracts ; it is 
almost as dependent on the purely vegetative part of the plant 
as is the scape of a holosaprophyte. Hence it differs from the 
latter only in the more numerous stomata and the larger inter- 
cellular spaces of the four-layered cortex. 
General Summary on the Morphology and Physiology * 
of Orchidaceous Saprophytes. 
1. The first general characteristic is the relatively large deve- 
lopment of subterranean parts of the plant, and the dwindling of 
the parts protruding into the air. The food comes solely from 
the substratum and is entirely absorbed by organs lying in it. 
No nutriment is taken in by the aerial parts. A saprophyte 
may be compared to a submerged water-plant which has pre- 
served its ancestral mode of producing flowers protruding into 
* As all the physiological conclusions in this paper are drawn from 
analogy and from morphological observations, they must be regarded as 
tentative. 
