ON THE USE OF THE TERM "VARIETY"
IN SYSTEMATICS.
BY
L. J. Sedgwick, F.L.S.
The remarks which follow are based on practical experience as a field worker only, and the writer hopes that readers of the Journal will accept this limitation when considering them. The main questions brought up for discussion are : (l) whether the term variety as used in our Floras is applied to one natural phenomenon only, or at the worst to several phenomena which are perfectly homologous, and if not, then (2) whether there is any way of separating out the various phenomena hitherto confused under the one term, and assigning to each a separate term ; since it is clearly unscientific to use one and the same term for phenomena which are heterologous.
It is usually assumed that in all taxonomic work the personal equation enters largely, and cannot be eliminated. It is open to question whether the latter part of this assumption is correct so far as species and units lower than the species are concerned. So far as concerns genera, families and all units above the species, since these taxonomic divisions are based on assumed descent, and since for the descent of plants our only material is the very fragmentary palasontological record, it is clear that our results must largely depend upon guess work. And it is for that reason that the tendency of even our deepest systematic thinkers to allow their generic divisions to be (sometimes at any rate) influenced by considerations of convenience is a comparatively venial sin. In the case of species however and all intra-specific units—excluding of course extinct species—there is no possibility of pleading lack of evidence. If into our discrimination of species the personal equation enters the fault is ours. We are hampered by weakness of power of perception, by shortage of workers, by lack of time, and by idiosyncrasies that could be eliminated. But the truths are there if we could only unravel them. In the case of most "critical" species the number of available individuals is legion. Mendelian and other experiments could be carried out. Even if the species or group of species is in an active state of evolution at the moment its different forms and developmental tendencies could be enumerated and charted. For instance, to take an imaginary case of an Indian genus believed to be in an active condition of
