160 SYNGENESIA. SUPERFLUAr 



late or tubular. Receptacle r\iikv(\. Pappus smi^ 

 pie, sessile. (Flowers mostly polygamous, dioi- 

 cous.) 



Leaves radical, often large; scapes squamose, 1-flov.ered^ 

 or tliyrsoidiy spiked, mostly appearing before iIk- leaves. 



Species. l.T. frigiuii. 2.sagittata. Herb. Banks, mss. 

 3. palmaia. t) r. On tlit: islands of Lake Huron, ijear 

 Michiliniakinak, in Fir woods, fAbies CcoiadeasisJ. The 

 leaves considerably resemble those of PoclophijUum pel- 

 fatum. 



A genus almost exclusively European, with the above, 

 2 species in Siberia and 1 in Patagonia, excepted. 



566. ZINNL\. L. 



Calix ovate-ryliiKiric, imbricate. Bays 5, 

 persistent, entire. Receptacle paleaceous. Rap' 

 pus 2 erect awns. 



Herbaceous; leaves opposite, rarely verticillate; flowers 

 solitary, terminal; rays red or yellow. 



Species. 1. Z. midtif-ora. A doubtful native. 



A genus of 5 species, all probably indigenous to Mexi- 

 co, with the exception of Z. paudfora of Peru. 



567. BOEBERA. 7Filldenou\ 



Calix doubl;-^, exterior niany-Ieaved^ interior 

 8-leaved. Receptacle naked. Rappiis pilose. 



Annual; leaves opposite, pseudopinuiite, and as v^^ell as 

 the calix glandular; peduncles 1-fiov.ercd, dichoiomal and 

 terminal. Inner calix about 12-leaved, exterior or invo- 

 lucell about 8-leaved, spreading. Ra} s about 8. Pappus 

 pilose, short. Nearly allied to Tageica. 



Species. 1. B. glandulom. A common weed on the 

 banks of the Mi6sisip{)i and Missouri to the Mountains, in 

 denudutcd soili. — Stem decumbent and much branched. 

 Flowers small and yellow; calix campar.ulate, and as well 

 as the leaves, beset wi-.h the same foetid resinous glands 

 as 'li.getes and diifusing a similar llutaceous odor. — The 

 only species of the genus. 



568. >^TRICHOPHYLLUM. t 



Calix oblongcylindric, raany-leaved, equal. 



-j-The copious pubescence, particularly distinguishing these 

 plants from the genus Tajetec. 



