THE 



CANADIAN 



NATURALIST AND GEOLOGIST. 



Vol. IV. FEBRUARY, 1859, No, 1, 



ARTICLE I. — Remarks on the Geographical Distribution of the 

 Cruciferce throughout the British Possessions in North 

 America. By George Barxston, Esq. 



(Fresented to the Montreal Katural History Society.) 



In bringing Cruciferjs forward immediately after Fumariace.e, 

 Torrey, with Lis usual acumen, has followed the surest indica- 

 tions of relationship. In these two orders the petals and stamens 

 are equal is number, and the superior ovary is formed nearly 

 on the same plan with Parietal Placentae. In both the sepals 

 are deciduous, and those of Fumariacse we might almost look up- 

 on as four, but united into two. The differences which do exist 

 are not so great as to neutralize the above resemblances in cha- 

 racters so essential to the formation of a natural system. That 

 profound observer Jussieu, also, at an earlier date, did not fail to 

 allow their due weight to these decided marks of propinquity. 



Of the species of Cruciferje to be found in North America, 

 Torrey and Gray describe 113. Of these, there are probably ten 

 that have been introduced, and perhaps nearly as many are com- 

 mon or indigenous to both North America and Europe. The nine 

 or more tribes into which these cruciferae are divided, derive their 

 characters from the length or shortness of the silique, its dehiscence 

 or indehiscence, the arrangement of the seeds with regard to the 



Canadian Nat. 1 vol. iv. no. r. 



