Studies in the North American Convolvulaceae. I. 



Homer Doliver House 



476. 



Jacqiiemontia Choisy (Mem. Soc. Phys. Genev. 6 : 



/ 



/< 



tp/i 



1899). 



Following the type adopted by Choisy, all the species without the 

 capitately clustered inflorescence and foliaceous bracts should be 

 retained in Jacqiiemontia. Those species having the large foliaceous, 

 hairy or pubescent bracts and densely capitate inflorescence form 

 a natural group worthy of generic recognition. 



THYELLA Raf. Fl. Tellur. 4 : 84. 1836 



Annual or perennial twining or upright herbs. Leaves alter- 

 nate; blades entire or lobed. Flowers in dense capitate clusters, 

 interspersed with numerous enlarged and foliaceous bracts, the 

 outer ones usually the largest ; bracts and sepals often shaggy or 

 densely pubescent. Sepals narrow 7 , equal. Corolla blue, violet 

 or white, the limb plaited, campanulate, 5-angled or 5-lobed. 

 Stamens 5, not surpassing the corolla. Ovary 2-celled ; styles 

 united up to the two ovoid, flattened stigmas. Capsules sub- 

 globose, 4-valved. Seeds minutely roughened. 



Type species, T. tamnifolia (L.) Raf. 



Represented by about 12 species, mostly South American, the 

 three following occurring in North America :* 



* The following species of tropical South America should also be referred here : 



Thyella acrocephala (Meissn.) 



Jacquemontia acrocephala Meissn. in Mart. Fl. Bras. 7 : 302. 1869. 



Thyella bracteosa (Meissn.) 



Jacqiiemontia bracteosa Meissn. /. c. 304. 



Thyella Choisyana (Meissn.) 



Jaequemontia Choisyana Meissn. /. c. 302. 

 Ipomoea lacioclados Choisy ; Meissn. /. c. as syn. 



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