138 ONAGRACEAE 



1. P. petiolata (L. ) Rusby. TAR WEED. A viscid-pubescent annual, 

 G'-IS' high : leaves ovate-lanceolate, petioled, entire : petals purple. 

 Often very abundant on dry hills. July-September. 



FAMILY 90. ONAQ-RACEAE Dumort. 



Herbs with regular perfect flowers, the parts in twos, fours or more. 

 Calyx tube adnate to and sometimes prolonged beyond the ovary. Sta- 

 mens and petals (when present) inserted on the summit of the calyx 

 tube. Ovary 1-4-celled. Stigma capitate or four-lobed. Ovules 

 numerous. 



Parts of the flowers in fours or more. 

 Seeds not long silky-tufted. 



Calyx tube divided to summit of ovary. 



Stamens 4. 1. LUDWIGIA. 



Stamens 8-12. 2. JUSSIAEA. 



Calyx tube prolonged beyond the ovary. 

 Flowers yellow. 



Stigmas 4-lobed. 4. OENOTHERA. 



Stigma discoid. 6. MERIOLIX. 



Flowers reddish to white. 



Ovary 4-celled. 5. HARTMANNIA. 



Ovary 1-celled. 7. GAURA. 



Seeds long si Iky- tufted. 3. EPILOBIUM. 



Parts of the flower in twos. 8. CIRCAEA. 



1. LUDWIGIA L. 



Herbs with axillary flowers and entire leaves (in ours). Parts of the 

 flowers in fours. 



Leaves opposite. 1. L. palustris. 

 Leaves alternate. 



Petals none or minute. 2. L. polycarpa. 



Petals large and conspicuous. 3. L. alternifolia. 



1. L. palustris (L.) Ell. MARSH PURSLANE. Creeping or floating : 

 leaves ovate, petioled : petals minute or none : flowers nearly sessile : 

 capsule 4-sided. Ponds and low grounds in the vicinity of Lake City. 

 Infrequent. July-September. 



2. L. polycarpa Short & Peter. 1-2| high : leaves linear-lanceolate, 

 those of the runners spatulate : flowers sessile : capsule top-shaped, bracted 

 at base. Low grounds near Lake City and Sibley. Local. July-Sep- 

 tember. 



3. L. alternifolia L. l-3 high : leaves lanceolate : flowers short- 

 peduncled : capsules cubical, wing-angled. Frequent in moist places 

 throughout. June-September. 



2. JUSSIAEA L. 



Calyx tube elongated. Capsule long-linear. 



1. J. diffusa Forskl. Creeping : leaves oval-oblong, entire, petioled : 

 petals yellow, five : sepals five : capsules long-peduncled, linear, terete.- 



