299 
greatest help has come from the collections in the British Museum 
and in Hanbury’s Herbarium atthe Pharmaceutical Society of Great 
Britain. The Council of the latter Society have placed me under 
a special obligation by sending the whole of the Andropogoneae 
of that valuable collection to Kew in order that I might study it 
at leisure. For this liberal and courteous assistance I wish to 
express my sincere gratitude to all concerned. 
In this paper I have endeavoured to embody the results of my 
researches into the history and taxonomic position of the oil-grasses 
of India and to introduce the necessary changes in their nomencla- 
ture. I hope to have laid the foundation for a more satisfactory 
conception of those grasses as taxonomic units. At the same time 
Tam well aware of the incompleteness of my work and the inevitable 
defects of research carried on to a great extent with material which 
has been collected casually or at least without consideration for the 
requirements of the problem as it presents itself to-day. Moreover, 
certain questions, some of them of great theoretical and practical 
importance, can, at the herbarium table, only be approached by 
a method of inference. The conclusions arrived at in this way 
will carry more or less weight according to the number and pre- 
cision of the data which the specimens present. I have in view 
more particularly the question of “ variability ” on which so much 
depends for the correct: co-ordination and subordination of forms. 
The notes we have on this point from collectors and others who 
have had opportunities of observing the oil-grasses in their natural 
stations or in cultivation are few and extremely meagre. 
Systematically conducted experiments there are none. When 
this is the case the taxonomist has generally to fall back on his 
‘tact’; but valuable as this somewhat ill-definable quality in 
certain circumstances may be, conclusions based on it cannot be 
accepted as final so long as they have not been confirmed by 
extended and direct observation in the field and by experiment. 
Work of this kind must therefore necessarily be more or less 
incomplete and preliminary. Nevertheless, it is a conditio sine 
qua non for systematically conducted field-work and experiment. 
It provides field-workers with a starting basis and with the means 
of checking the identity of the plants under observation. In return 
it will no doubt one day receive its corrective from that quarter. 
In discriminating and defining the species which are here under 
consideration I have so far relied on external characters. They 
might, and certainly will, in the future be supplemented by 
anatcmical characters. I have not carried my investigations in this 
direction far enough for publication, but sufficiently far to see 
that they promise especially the possibility of greater precision in 
the description of some of the external characters. For naming 
purposes the anatomical characters will hardly be required in cases 
where complete material is at hand; but they may be of value 
where, for instance, as is sometimes the case, barren plants have 
to be determined. 
How far they may influence the classification of the oil-grasses 
it is premature to say ; but I would quote Hackel’s* observation on 
the taxonomic value of anatomical characters in Andropugoneae 
* Andropogoneae in DO, Monogr. Phaner., vol. vi., p. 17. 
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