160 ONAGRACE.E. (EVENING-PRIMROSE FAMILY.) 



recurved. Fruit bony, 4-celled, 4-lobed, iudehiscent. Aquatic perennial 

 herbs, with the submerged leaves pinnately divided iuto filiform or capillary 

 segments, and commonly whorled. Flowers minute in the axils of the upper 

 leaves ; the uppermost sterile. 



* Stamens 8 : fruit even or wurtij. 



1. M. laxum, Shuttlw. Stem long, slender; leaves 4 in a whorl; the 

 floral onus reduced to minute nearly entire spatulate bracts, shorter than the 

 flowers, which thus form an interrupted almost naked spike; fruit roughened 

 with minute warts, with the lobes obtuse. Ponds and lakes, Middle and 

 West Florida. July. 



2. M. verticillatum, L. Leaves in whorls of 3-4, the floral ones lin- 

 ear, pectiuately toothed, much longer than the flowers ; fruit smooth. Still 

 water in the lower districts. Julv. Stem 2 -4 long, stouter than the last. 



* * Xtumi-ns 4 : fruit ridijcd and roughened. 



3. M. heterophyllum, Michx. Stem thick; leaves 4- G in a whorl, 

 the floral ones crowded, ovate or lanceolate, finely and sharply serrate ; the 

 lower ones piunatifid ; fruit slightly roughened. Ponds and ditches. July. 



4. M. SCabratum, Michx. Stem short (6'- 12'); leaves 4-5 in a 

 wlmrl, the divisions few and capillary, the floral oues linear, pectiuately 

 toothed ; fruit strongly ridged and roughened. Shallow ponds, South Caro- 

 lina. June - July. 



ORDER 60. OlVAGRACEvE. (EVENING-PRIMROSE FAMILY.) 



Calyx adherent to the ovary, and often produced into a tube beyond 

 it, 2-G-lobed, valvate in the bud. Petals as many as the lobes of the 

 calyx, inserted on its throat, convolute in the bud, sometimes wanting. 

 Stamens as many or twice as many, inserted with the petals. Ovary 

 2 -4-celled. Placenta central. Style solitary : stigma capitate or 2- 

 4-lobed. Capsule loculicidally dehiscent or indehisceiit. Seeds anat- 

 ropous, with little or no albumen. Chiefly herbs. 



Synopsis. 



* Calyx tube produced beyond the ovary. 



1. GAURA. Capsule nut-like, iudehiscent, 1 -4-seeded. 



2. CENOTHERA. Capsule 4-valved, many-seeded. 



* * Calyx tube not produced beyond the ovary. 



3. EPILOBIUM. Stamens S. Petals 4. Seeds comose. 



4. JUSSI^A. Stamens 8 -12. Petals 4 -G. Capsule long. Seeds naked. 



5. LUDWIGIA. Siamens 4. Petals 4, or none. . Capsule short, many-seeded. 

 G. CIRC^A. Stamens 2. Capsule obovate, 1 -2-seeded. 



1. GAURA, L. 



Calyx tube much produced beyond the ovary, the limb 3 -4-lobed, reflexed, 

 deciduous. Petals 3-4, clawed, unequal or turned to the upper side. Sta- 

 mens 6 -8. Style declined : stigma 4-lobed. Ovary 3 - 4-celled. Fruit 3 -4- 



