32 Sterna callosa. 



der. Anthers blackish. Stigma bifid. Receptacle naked. Seed conic, 

 pentangular, terminated by a short eroded paleaceous pappus. This 

 species, excepting in the calix, does not essentially differ from Hyme- 

 nopappus."* 



This is the first North American species of this Mexican genus which 

 has been discovered. Plant debile. Stem simple below, branched above. 

 Flowers peach-blossom-red, as they grow older they become very pale, 

 a faded red or almost white. Flower-buds deep lake-red. Stem light 

 siskin-green, argentine, and shining, rather rough to the touch, owing to 

 a very short, stiff pubescence, almost imperceptible except under a lens. 

 The leaves have a nerve on each side of the costa and near the mar- 

 gin, which is somewhat channelled, or slightly scabrous; under a lens 

 covered with the same kind of hairs as are on the stem ; the branches 

 which bear the flowers are without the argentine lustre, and more con- 

 spicuously pubescent and roughish; peduncles, and forks which bear 

 them, covered with a conspicuous, glandular pubescence of a brown 

 colour; many of the leaves, particularly the branch leaves, arcuate, and 

 all of them, without exception, terminating in an obtuse, yellow, spha- 

 celated dot. Grows on the gravelly banks of the Arkansa, rare. Flowers 

 from September till October. 



The table. Figure l, Represents a flowering portion, of its natural size. 



2. A flower, separated. 



3. The same, magnified. 



* Jour. Acad. Nat. Sc, Phil. 1821. 



