SYNGENESIA. SUPERFLUA. 171 



578. ACMELLA. Richard, 



Calix sim])le, leaficis few. Receptacle oblong, 

 paleaceous. Seeds 4-3ided, truncate at the sum- 

 mit, naked. 



Herbaceous, stems mosty prociunbent, lea\;es opposite, 

 entire; peduncles solitary, i-flowereci, axillary and termi- 

 nal. Flowers yello>v. Kays oblong. 



Species. 1. A. repeiis. Spilanthus repens. Mich. 2. occi- 

 dentalism Hab. On tlie banks of the Missisippi neat* 

 _ New Orleans. Ob3. Stem repent^ .«!onne\vilat pubescent. 

 Leaves ovate, crenate, obsoleteiy 3-ncrved, smooth and 

 petiolate; peduncle axillary and grooved, about 3 inches 

 long-; rays 5 to 8r; caiix minute. Resembles a small Hud' 

 bcckia. 



A g'enus of 5 or 6 species indif^enous to the warmer 

 parts of Amei'ica, not essentially disiiuct from Ueliopsis 

 either in habit or chai-acter. 



o79. ANTHEMIS. L. (Mayweed, Chamomile.) 

 Calix hemispherical, subequal. Bays more 

 than 5. Receptacle paleaceous; palese ilat, with 

 rigid acuminated points. Pappus none or mar- 

 ginal. 



Herbaceous; leaves mostly multind; ramuli usually 1- 

 fiowered; rays white or yellow, rarely wanting. 



Species. 1. A. nobilis. Common Chamomile. Natural- 

 ized near Lewistown, Delaware. 2. Cotula. May-weed. 

 Introduced, but now every where a common weed in 

 ■wastes. 



A genus of about 25 species, almost exclusively indige- 

 nous to Europe. 



530. ACHILLEA. L. (Millfoil.) 



Ca/Lr ovate, imbricate. Rays 5 to 10, round- 

 ish. Receptacle paleaceous. Fappus none. 



Herbaceous, seldom sufif'ruticose; leaves multifid or rare- 

 ly undivided; flowers corymbose; rays white, reddish or 

 yellow. 



Species. 1. A. Afillefolium. Naturalized, ^tomcntofa. 

 Upper Louisiana. Fh. 3. asplenifolia. A variety of ^f. Mil- 

 lefoliwn? 4. Ptaruiica, Sneezewort. From Canada to New 

 iork. Ph. 



