MANY keys to the identification of coniferous timbers have already been published, but for one reason or another these all fall short of the requirements of a wood technologist faced with the task of identifying the numerous timberproducing species. Some of these keys are based on material too limited, and fail to take account of the variation shown within the limits of individual species, or deal with material of very young stems or branches, the anatomy of which often differs markedly from that of the adult wood which constitutes the major portion of the trunk. Several of the keys available deal only with very limited numbers of species-for example, the extent of a small collection, the species of one particular geographical region or the members of a single taxonomic group-and are difficult to apply when identification problems are not similarly circumscribed. Moreover, all the published keys are of the dichotomous type, and consequently suffer from the disadvantage that the features of any particular wood have to be examined in a fixed order, although these may not be readily determinable with certainty on the small samples frequently submitted for identification. If a doubtful determination has to be made early in such a key, then even an approximate or group identification is precluded. Another disadvantage of the dichotomous key is that modifications or additions suggested by further experience cannot readily be made.The primary object in preparing the present key was to provide a comprehensive guide to the identification of those softwood timbers of commercial importance. After careful consideration, it was decided, however, to include in the key not only representatives of the twenty-three genera which have been met with in the course of several years contact with the timber trade, but also representatives of all other genera producing sizeable trees. Descriptive notes on the remaining genera, mainly compiled from the literature, me recorded for reference purposes, but these genera are not included in the key.In order to overcome the difIiculties associated with dichotomous keys a 'multiple entry' key of the type described by Clarke (1938) has been developed, the characters of each species being recorded on cards which have marginal series of perforations (see text- fig. 42) and are adapted for rapid mechanical JOURN. LINN. S0C.-BOTANY, VOL. LII

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