PRELIMINARY TREATISE. 
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good for nothing as characters of natural groups, though 
valid in generic separations, it is sufficient to name Haeman- 
thus with a pulpy berry-like fruit, and Buphane with a 
valved capsule, yet so closely allied that they have been 
heretofore considered one genus, and are not distinguished 
by any other striking feature. The shape of the seed-pod 
cannot be relied upon with certainty, even as a generic dis- 
tinction ; and Linnaeus, when he divided tetradynamia into 
siliculosa and siliquosa made a very unsatisfactory separa- 
tion. The simple fact, whether the seed is naked or covered, 
furnishes, perhaps, a limitation of more value, if any have 
it really naked, but it does not help us to subdivide mono- 
cotyledonous plants, because they all have it covered, except 
where it is exposed by the early disruption of the pericarp. 
It is something to have cleared the way of features which, 
though they have been used, are evidently not available as 
the distinctions of natural groups ; and although these con- 
siderations, when duly appreciated, must shew the necessity 
of superseding a great part of the present arrangement, they 
will help to lead us to something more substantial. I will 
suggest, as well as the limited information 1 possess will 
enable me, the features that appear to me to separate the 
monocotyledonous plants into natural groups, calling to mind 
that natural groups are properly such as will strike the un- 
scientific eye as having some general resemblance, without 
searching for a minute point of agreement. I have to re- 
gret, that in order to ascertain any one point concerning any 
class of vegetables, it is necessary to examine afresh almost 
every plant of which it consists, from the silence or lax ex- 
pressions of botanists, and the absolute falsehood of many 
of our engravings in material points ; and, with respect to 
the venation of leaves in particular plants, our books are 
generally silent, and the engravings frequently give an un- 
true representation, so that I cannot obtain the information 
I desire. 
The palms, aroid, and piperaceous plants, form a con- 
spicuous division amongst the monocotyledonous plants, 
and the spadix seems to me the great point of agreement. 
Spadix originally meant the inflorescence of the palm, that 
is to say, flowers without the semblance of a corolla, closely 
set round a stalk which has an involucre below. There is a 
defective spadix, which w'ants the involucre, in piperaceous 
plants and bidlrushes ; and there may, perhaps, be a dif- 
