KNOWLEDGE OF MONOCOTYLEDONOUS SAPROPHYTES. 207 
rhizomes, for in them there is an extensive development of hairs 
which function as absorbing-cells. In Epipogum nutans the 
rhizome-axis is smooth and does not absorb: it is covered by 
relatively large scale-leaves which take in the food, and for this 
purpose produce a great number of greatly elongated narrow 
hairs (compare Dictyostegia orobanchoides). On the other hand, 
in the green Corysanthes sp. the (2-8) subterranean scale-leaves 
are small and smooth and do not take in the food; but the axis 
bears numerous absorbing-hairs perched upon multicellular 
outgrowths. Similar outgrowths occur on the rhizome of Coral- 
lorhiza innata. Epipogum aphyllum contrasts with Epipogum 
nutans in that, in the former, the axis produces the absorbing 
hairs, and the transitory leaves are smooth. 
Concerning the absorbing-organs of orchidaceous saprophytes, 
three features are noticeable :—(i.) that they lie in the superficial 
layers of the substratum; (11.) that their volume is increased rela~ 
tively to the surface (compared with typical roots of ordinary 
plants); (ij that the absorbing-cells, including hairs, function 
Jor a long time, and do not die speedily as do the root-hairs of 
normal terrestrial plants. The object of these arrangements is 
tolerably obvious. The humus-giving bodies are present in 
greatest quantity at the surface of the substratum and in the 
layers immediately below. Hence the absorbing-system will live 
in these upper layers. In addition, new supplies of food come 
constantly from above. Thus there is no need for the manu- 
facture of new absorbing-organs to penetrate into and exhaust 
deeper regions of the soil; the old feebly-branched roots or 
rhizomes and the old absorbing-cells are all that are required, 
because the food comes to them. 
Essentially connected with the absorbing-organs are the my- 
corhizal hyphx, which are present in all known saprophytes 
(excepting Wullschlegelia, according to Johow). The function 
of mycorhiza is still a mystery. All that is known is that certain 
plants have on or in their roots mycorhizal hyphe ; that mycorhiza 
is absent from roots growing in soils devoid of humus; and 
that in the case of endotrophie mycorhiza the fungus does 
not kill the protoplasm of the cells in which it dwells. But tbese 
facts do not entitle us to assume that the fungus exerts a bene- 
ficial effect on its host; and Frank’s observations (on Beeches 
and Conifers) are too meagre and uncritical to be considered as 
proving anything. Still the distribution of the hyphe (9) in 
