6 MR. G. BENTHAM ON THE 



Nemacladm 



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the two former from western extratropical America (south and 

 north), the latter from South Africa, which have very decidedly the 

 irregular corolla of Lobelieae with the free anthers of Cainpanulea?. 

 We have for technical convenience placed them together in a 

 small third tribe intermediate between the two others ; but, strictly 

 speaking, they may not perhaps form a truly natural group. In 

 general character indicative of natural affinity, each one of the 

 three may prove to be more nearly allied to some one belonging 

 to one of the other tribes than to either of the two now associated 

 with it ; but yet the actually inserting them in those tribes would 

 have interfered too much with a clear methodical exposition of 

 the order to be admissible at present, besides that it is by no 

 means certain that they have not a common connexion. 



An elaborate and careful monograph of the tribe Campanulas 

 was the first botanical publication of Alphonse De CandoUe, and 

 gave him at once a distinguished place amongst the followers of 

 systematic botany, although that has never been his special branch 

 of the science. He subsequently edited the whole group for the 

 1 Prodromus ; ' and he may always be relied upon for accuracy of 

 detail as far as his own observations went. If we have found it 

 necessary to remodel some of his genera consisting chiefly or en- 

 tirely of extra-European species, or to lower the systematic grade 

 he had assigned to some of his groups, this is owing either to the 

 additional lights thrown on the subject by subsequent discoveries, 

 or, in the case of several Lobelieae, to the too great reliance 

 placed by him on the preceding observations and conclusions of 

 Presl and Don ( George Don, assisted, I believe, in many respects 

 by his brother David), many of which are very loose and hasty. 



The Lobelieae, however, are exceedingly difficult to divide into 

 definite genera. The most dissimilar groups often run into each 

 other by almost insensible gradations. I have endeavoured to 

 keep up all genera which appeared to be founded on more appre- 

 ciable characters, such as the consistency and dehiscence of the 

 fruit, the placentation of the ovary, the dorsal or ventral fissure of 

 the corolla, the attachment of the stamens, &c. But I have felt 

 obliged to leave the genus Lobelia itself a very large one, however 

 heteromorphous it may appear at first sight. The St.-Helena 

 Trimeris, the large tropical species which I have referred to the 

 section Bhynchopetalwn, the Central- American section Homochilus, 

 the large scarlet North-Ameriean Euhbeli<t. and the small Mm 



