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



picrpurei : nervis infra sinus laciniarum dichotomis. Pappus 

 niveus. 



1. A. formosa. 



In Mexico. Sesse et Mocinno. ^ . 



This genus agrees with the preceding in the structure of its 

 involucrum, and with Trixis in the indefinite number of its 

 florets ; but it is distinguished from both by its naked recep- 

 tacle, and from Clarionia by the structure of its pappus, by its 

 equal florets, as well as by its widely different habit. 



I have dedicated this very distinct and interesting genus to 

 Mrs. A'Court, of Heytesbury House, Wilts, whose botanical 

 taste and knowledge have long merited for her this compli- 

 ment. 



Clarionia. Lag. et Dec. 



Perezia. Lag. Amen. Islat. 1. p. Si. 



Receptaculum nudum. Flosculi indefiniti. Pappus capillaris. 

 Involucrum polyphyllura, imbricatum. 



Involucrum oblongum, cylindricum, multiplici ordine polyphyl- 

 lum, imbricatum. Receptaculum nudum. Flosculi omnes 

 hermaphroditi, bilabiati ; marginales majores, radium aemu- 

 lantes ; labio exteriore longo, ligulato, 4-nervio, obtus^ tri- 

 denticulato, patulo ; interiore profundi bipartito : segmen- 

 tis lineari-angustissimis, binerviis, apice attenuatis, spi- 

 raliter revolutis, primo margine conglutinatis, uti saepii'is 

 perfacilfe pro unico et simplici habitis ; disci multoties bre- 

 viores ; labio exteriore elliptico, concavo, obtus^ tridenticu- 

 lato ; interiore bipartito, spiraliter revoluto : segmentis simi- 

 liter conglutinatis, at latioribus. Filamenta capillaria, gla- 

 bra, articulo manifesto. Anthera appendicul4 lineari, acut^, 



cartilagineo- 



