174 Mr. D. Don's Descriptions of new Genera and Species 



Ac HEN I A nunc apice calva, 



Plantae lactescentes. Folia alterna. Flores saepu\s lutei. 



This family constitutes but a very small part of the Compositce 

 in the South American Flora, being scarcely in the proportion 

 of one to forty-five, while in the European Flora they are gene- 

 rally as one to two. The dehor acea are readily distinguished 

 from the other families of Compositce by their uniform, ligulate, 

 hermaphrodite florets. The primary vessels are five in the 

 tube, but at the sinus, where the corolla splits open and expands 

 into the ligulate lamina, the interior nerve divides into two 

 simple branches, which run along the opposite sides, either 

 directly on the margin itself, or more frequently placed a little 

 within the border. The apparently simple trunks of the inter- 

 mediate vessels divide a little below the sinus of the teeth, and 

 traverse their margins, uniting at the summit of each tooth ; 

 but I have only in one instance, that of Prenanthes virgata of 

 Michaux, detected secondary vessels, and therefore conclude 

 that they are rarely present in the plants of this family. The 

 disposition of the vessels in the lamina of the corolla will be 

 found an important character in distinguishing the Cichoracece 

 from such individuals belonging to other families, whose florets 

 may have assumed an analogous form. 



Besides being lactescent, the alternate leaves, their nervation, 

 and the inequality of their teeth, when present, the irregularity 

 of the corolla in Lobelia, the cohesion of its antheras, and its 

 papillary stigmata, show that many analogies exist between this 

 family and Campanulacece. 



Trib. 1. HiERACEiE. Receptacidum epaleatum. Anthera basi 

 interiore ligula simplici membranace^ truncate auctae ! In- 

 volucrum polyphyllum. 



HiERACIUM. 



