KNOWLEDGE OF MONOCOTYLEDONOUS SAPROPHYTES. 197 
The conducting xylem, mainly composed of pitted tracheides 
in Galeola, is more completely developed in the inflorescence- 
axis than in the absorbing roots. In Epipogum the xylem of the 
absorbing rhizome is immensely developed and is composed of 
wide spiral-reticulate tracheides (or trachex) ; it is more feebly 
represented in the inflorescence-axis and, in fact, largely replaced 
by an intercellular space. 
Throughout, the plant Galeola is covered by cells with very 
thick cuticularized walls excepting over the patches on the inner 
faces of the scales; the intercellular spaces are small; mechanical 
tissue is greatly developed in the cortex and in the stele. 
Galeola is structuraly a xerophyte. Throughout, the plant 
Epipogum is covered by cells with very thin walls, possessing 
only a thin cuticle or not one at all; the intercellular spaces 
are large; there is no mechanical tissue whatever. Epipogum 
is structuraly a hygrophyte as regards its superterranean 
parts. This may be due to the habitat (the plant being found 
in wet dark places), or possibly is associated with the structure 
of the subterranean parts, 7. e. the great production of absorbing 
hairs tends to allow the shoot above ground to be less xero- 
phytie, and the presence of a large water-reservoir further acts 
in the same direction (compare thin leaves of orchids with 
pseudo-bulbs). 
COoRYSANTHES, sp. 
Our knowledge of terrestrial orchids in Europe leads us to 
infer, as did Reinke, that many green forms growing in substrata 
rich in humus are hemisaprophytes. Remembering further that 
holosaprophytes usually are characterized by the possession of 
colouring-matters,—the presence of a prominent colouring-matter 
in green terrestrial orchids or the absence of chlorophyll from 
certain parts of their leaves would cause us strongly to suspect 
such orchids of hemisaprophytism. In the hope of obtaining 
some structural evidence of this view, I asked Mr. H. N. Ridley 
if he would be good enough to send me any Malayan terrestrial 
orchids which were found growing in a nidus rich in humus and 
having a habit more or less like Anectochilus. In reply Mr. Ridley 
kindly sent me a species of Corysanthes which he found growing 
on shaded rocks which were carpeted with moss. 
Judging by the habitats of its species, Corysanthes seems to bea 
hemisaprophyte. Blume (7) gives the habitats of three Malayan 
LINN. JOURN.—BOTANY, VOL. XXXI. P 
