IV 
PREFACE. 
successively in the ‘ Annals of Natural History/ and no one has attempted 
in this interval to disprove the truth of the facts then stated : hence my 
conclusions on this subject may be taken to be silently, if not formally 
acknowledged. 
Subsequently I attempted, in the same manner, to show that a similar 
error had been committed in associating the Symplocinece with the Styra- 
cmea, two tribes constituting the order Styraceoe of DeCandolle. I was 
induced to extend this investigation by careful analyses of a great number 
of the species of both tribes, and was enabled to point out the very 
essential difference in the normal structure and subsequent development 
constant through both of them. This evidence demonstrates that the 
SymphcinecB should constitute a family {Symplocacece) distinct from Sty- 
racece, and should be placed in a distant position in the system. All the 
facts regarding the latter family, as they appeared originally in the ‘ Annals 
of Natmal History,’ are here again brought together, and rendered more 
obvious by analytical drawings : those relating to the SymphcacetB will be 
published at a future time. This investigation likewise required the 
utmost care and precision, because it involved the necessity of opposing 
the authority of two eminent botanists. It is fair to remark that, after 
the lapse of some years, the validity of my conclusions has not been 
challenged. 
The results of my subsequent investigations prove the importance of the 
object aimed at in my previous discussions respecting the nature of the 
outer seed-coats of the ClusiacecB, and especially of the arilloid tunic of 
Magnolia. The reception which my views on this question met with only 
stimulated me to further exertion, and led to my observations, which will 
be found in this volume, on the early formation and subsequent mode of 
growth of the ovule, — an investigation undertaken to mark, by the develop- 
ment of the raphe, the tests by which the true integuments of seeds may 
always be distinguished from those of adventitious origin or of arilliform 
growth. The reasons that actuated me in the agitation of this question 
