20 
>subsequeiit reference, -wliich is on the next page, states 
only, '' Omithochiliis U^all has two Himalayan or Burmese 
species, regarded by Lindley as a section of Aeridesj but 
in many respects coming nearer to Saccolabium^ and con- 
necting our second and third series of the sub-tribe 
Sarcffniheac ; and the connection is still further established 
by Saccolahium hillHF. Muell. from Australia which ^xe 
would add as a third species to Ornithochilu^i. 
if this position be accepted the question then arises 
as to where the plant can be placed, and the question is 
made even more vexed by tlie fact tiiat the sub-tribe to 
which it belongs consists of a large numl)er of geJiera eacli 
separated from the otlier l>y small but important factors. 
Hooker (10) stated, “ The classification of the genera of 
this sub-tribe presents great difficulties,” and when dis- 
cussing the characteristics of ISarcanthus- and (deisostoma 
said, Sarcanthus and Cleisostonia are separated from 
Saccolabium, and from one another, by characters so 
minute and trivial, that they might Avell rank as sections 
of that genus, to which Ornithochitus might be added.” 
He did include Uncifera and Acampe under Saccolabiwm. 
His suggestion was not adopted and by modern writers is 
definitely J’e.jected. Even if the concept of Saccolahium 
were widcnied to include all its near allies and so form a 
polymorphic g(Oius, it is doubtful if the plant under 
discussion could be easily fitted into it; and as it stands 
the position wold be even more difficult. Again tabula- 
tion miglit show the position b(‘st 
Saccolahium 
Column-foot Absent 
Lot. lobes of labellum Small 
Mid-lobe of labellum Small 
Sac Without calli 
P. hillii 
Present 
Large 
Absent 
With a lc#ge callus 
Almost similar comparisons could be made with the 
remaining related genera. The shape and ornamentation 
of the labellum separate it from tlie genera grouped by 
Beiitham (11) as Series 2. and this or the column-foot 
divide it from those groups as Series 1 and Series 8. There 
is no genus known to the writer which combines the 
presence of a column-foot with such a condition of the 
labellum and it is for this reason that it is suggested that 
the genus Pcristcrauthus be erected for its accommodation. 
The writer Avishes to express his sincere thanks to Kev. 
If. M. K. Rupp, of Willoughby, N.SAV., and Mr. S. T. 
Blake, of the Herbarium, Brisbane, for their valued assist- 
ance in the preparation of this paper. 
