THE BOTANY OP SOUTH AMERICA. 151 



their flowers, ought also to form a distinct genus, which no 

 one would venture to propose : upon the whole, therefore, 

 I would recommend that the genus Habrothamnus be sup- 

 pressed, and its species arranged as a particular section 

 of Cestrum under that appellation.* 



I may here avail myself of the opportunity of observing 

 that the genus Laureria of Schlechtendahl, placed by some 

 authors among the Nicotianea is beyond doubt, identical with 

 the Juanulloa of Ruiz and Pavon ; it ought, therefore to 

 be placed among the Solanece, where also Marckea of 

 Richard, and Nectouxia of Kunth, should be arranged, as 

 they better agree with many of that tribe in habit, and 

 as nothing is known of the character of their seeds to warrant 

 their being placed among the Rectembryece. 



I have excluded Dunalia from the Cestrinea in the above 

 distribution, because nothing is known of the nature of its 

 embryo, and for other reasons before pointed out, (Vol. IV., 

 p. 332.) 



In external aspect there is a remarkable resemblance 

 between some species of Petunia, Nierembergia and Salpi- 

 glossis, so much so, that several able Botanists have referred 

 such plants to these three different genera ; but there exists 

 in the latter, certain decided characters that cannot be con- 

 founded with the two former : I do not allude so much to 

 the didynamous stamens, with a fifth sterile filament, as 

 to the more important one of its deeply reniform seeds, 

 a nd completely annular, and sometimes even spiral embryo, 

 while in the two former genera the embryo is nearly straight 

 But there is also another well-marked difference in the aesti- 

 vation of the corolla, a character of the utmost importance, 



* The' three known species of Habrothamnus thus forming a distinct 

 section of Cestrum would be arranged as follows : 



§ Habrothamnus. 



Cestrum fasciculatum (Habrothamnus fasciculatus, Endl.) 



Benthami. ( tomentosus, Bth.) 



— • Endlicheri. ( corymbosus, Endl.) 



