56
ILLUSTRATIONS OF INDIAN BOTANY.
These little resinous deposits occupy a prominent place in DeCandolle's characters both of
tribes and genera. Tausch, who strongly objects to DeCandolle's general arrangement, especially his suborders, and proposes a new one for Ihe acceptance of Botanists, excludes them from
his sectional or Tribal characters, hut adopts them in his generic ones. He derives the characters of his tribes from the external forms of the seed, altogether rejecting DeCandolle's sub-orders requiring dissection for their determination.and as being inconstant and not always applicable to the species referred to them. That his distribution is really an improvement on the arrangement he wishes to set aside, I am unable to say, my collection being too small to admit of
my entering into a comparison, but I suspect both will be found defective when the order is
better understood. One point in both, which I consider objectionable, is the great number of
sections and subsections — 3 suborders and seventeen tribes in DeCandolle's and — 12 tribes and
]9subtribes in Tausch's arrangement. The distinctions between these, are often so exceedingly
slight as to be quite inapprehensible by all who have not especially devoted themselves to the
study of the family and are in short unfit to form good generic characters. The circular method
of investigation, which is now rendering such important services to zoology, has not yet been sufficiently extended to botany, though much wanted, for the elucidation of such extensive and natural families as the present. This is much to be regretted, as it is in such instances only, we
are enabled to form a just estimate of the value of that, system. This therefore seems an excellent example by which to test its powers, as all previous attempts to produce a satisfactory
arrangement of the species of Umbelliferae, whether artificial or natural have fallen short of
the mark — simply it appears to me, from the authors having neglected in the first instance, to
determine the intrinsic value of the characters they employed in the formation of their sectional
subdivisions, and in the construction of their genera. As this knowledge is indespensible to
success in all systems, but forms the primary point of enquiry in the circular one, it promises
to succeed where others less attentive to this point have failed.
Linnseus's arrangement according the involucra for example, which has been objected toby even his most determined followers, as being a departure from his own principles of deriving all generic characters from the flower and fruit, seems notwithstanding, to bring together as natural assemblages of genera as the more highly wrought one of Koch and DeCandolle, simply because a uniform value is assigned to the sectional characters rand I should not be surprised yet to find some one returning to this despised organ for the primary characters of a new distribution. I confess I cannot suppose such an attempt wdl succeed in producing a natural arrangement, though I think very useful secondary characters may be obtained from the involucra. The proposal of Tausch, that of taking sectional characters from the external forms of the fruit, I think good, but so far as I am able to judge from his characters. is carried too far. Mr. Burnet gives a sketch on a similar plan, which is probably better,his characters being more easily apprehended. That they are the best that could be obtained is a point I am unable to determine, but as wire drawn distinctions are avoided, it promises well. Upon the whole, I am of opinion that the order still stands in need of an able monographist duly impressed with the conviction that most, if not all his predecessors, forgetting that the limits of sections and genera should be marked by broad lines easily seen, have erred in seeking to subdivide on the strength of minute and even theoretical characters when the adoption of other more obvious ones were open to them. Unfortunately for the science this is an error too easily fallen into, one, to which nearly all are liable, and to the extension of which, nothing is tending so much as the now nearly constant practice of giving very extended generic characters, or rather generic descriptions, including a number of useless particulars common perhaps to every species of the order, but which, when accidentally wanting, has sometimes the effect of causing varieties of the same species to be distributed as new species in different genera, and even raised to the rank of distinct, genera. That errors similar in kind have always been avoided in this order I am far from thinking, and to me it seems probable, if revised in the way I have suggested,a considerable reduction in the number of both genera and species will be affected with advantage to the whole. There are now known about 12QU species, for the reception of which no fewer than 200 genera have been constructed, surely a most unnecessary multiplication in an order so much alike throughout. As however the subject is one on which I can only reason hypothetically, my acquaintance with it being limited, 1 refrain from further remark having already I fear said more than is prudent.
