REVISION OF INDIAN SCREWPINES AND THEIR ALLIES. 99 
Much difficulty in working up a monograph of the genus Pandanus 
is caused by the very incomplete knowledge which we possess of the 
Mascarhen species. The number of them is considerable, in compari- 
son with the Indian species. I have not the advantage of being able 
to consult Gaudichaud's work, which, without doubt, would throw some 
light upon this matter. 
With reference to the sections which I have adopted, I must remark 
that they can be considered only preliminary ones. Of most species I 
have not had the opportunity of examining both sexes. In particular, 
it might be proved, by more complete material, that Ryckia and Micro- 
stigma must be somewhat remodelled. 
Eumphius (Herb. Amb. iv. p. 145) very originally remarks, " Cer- 
tum enim est Pandanos sat laboris causare curiosis ipsorum investiga- 
toribus, ut rite distinguantur ; puto autem non tanto dignos labore, 
quum ipsorum plurimi exiguum praebeat usum." This latter clause, 
however, may be doubted, considering that five-sixths of the Malayan 
population sleep on pandan mats only, and that many of them live en- 
tirely by making such mats, hats, etc. from the leaves of Pandanus. 
There is no doubt, so far as I am acquainted with the species of 
these peculiar plants, that Pandanus really includes protean forms in such 
a degree that it is difficult to give a good description of some of them. 
A long series of forms is often required to ascertain the real limits 
of a species, and this is here the more difficult, as we are mostly con- 
fined to our memory only. Though I had so extensive a collection of 
growing Screwpines at my disposal in the botanical gardens at Buiten- 
z °rg, I came to a conclusion only after examination of many conti- 
nental forms. Characteristic as the different species may be, there is 
scarcely any part of the plant which may not vary in any degree, and 
the stigmata themselves appear often very elongated in the one and 
shortened in the other form, but without therefore giving up their 
essential value. Iu the phalangeal group there frequently may be 
found a single free drupe amongst the phalanges. Such degrees of 
variation are the more to be attended to, as the varieties, owing to 
their arborescent growth, appear commonly very constant. Determi- 
nations of Screwpines in European hothouses I consider therefore 
quite insufficient, and only promoting the amount of synonyms. 
In the following pages I have enumerated all the gerontogeous 
species, partially because some of them may be found on the Indian 
