PREFACE,

which botanists have fixed on as the only means by which aplant, that is not familiar to the reader of a description of it,can with certainty be known, when he wishes to possess it, oris in any doubt regarding it when it is obtained. From thewant of this degree of accuracy in the descriptions of plants,many valuable remedies, used by the inhabitants of one part ofthe world, have been lost to those of another part, where theyare, nevertheless, indigenous; or, instead of the proper plants,other species of the same genera, which possess little or novirtue, have been employed; and even plants, not in anyrespect medicinal, but highly deleterious, have been used asremedies, merely from their bearing names in common or inpharmaceutical language similar to those of some medicinalplants. To prevent this evil, therefore, I have added to theusual account of each vegetable substance the characters ofthe genus to which the plant belongs, as they are given byWilldenow in his excellent edition of the Species Plantarum :and have also given detailed descriptions of each in the lan-guage employed by modern botanical writers.

In the performance of the task of compilation, I haveendeavoured to bring together as much useful information,regarding each of the substances treated of, as could becrowded into a small space; and to obtain it, have had re-course to every work of reputation to which I could gainaccess. For the liberality of Sir Joseph Banks, who, throughthe kind interference of Dr. Gartshore, opened to me thedoor of his princely collection, I have to return my mostgrateful thanks; as I obtained information there which Icould not otherwise have procured, and some which has neverbefore, I believe, been given to the public in an English garb.Of this nature, in particular, are the observations of Zea onthe medicinal species of Cinchona, extracted from the Analesde Historia Natural ,■ those of Humboldt on the same subject,and on some other South American plants, from his splendidwork entitled Plants JEquinoctiales; and Wiildenow's descrip-tion of the Heracleum gummiferum, which I have translatedfrom the Hortus Bcrolincnsis. Information has also been

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