266 



ONAGRACEAE. 



Family 7. ONAGRACEAE Dumort. 

 EVENING-PRIMROSE FAMILY. 



Herbs, or rarely shrubs, with alternate or opposite leaves, no stipules 

 or mere glands in their places, and generally perfect flowers. Calyx-tube 

 adnate to the ovary, the limb 2-6-lobed (usually 4-lobed). Petals 2-9 

 (usually 4), convolute in the bud, rarely none. Stamens usually as many 

 or twice as many as the petals. Ovary 1-6-celled (usually 4-celled) ; styles 

 united; stigma capitate, discoid or 4-lobed; ovules generally anatropous. 

 Fruit a capsule or small nut. Endosperm very little or none. Forty genera 

 and about 350 species of wide geographic distribution, most abundant in 

 America. 



Calyx-tube not prolonged beyond the ovary ; aquatic plants. 

 Calyx-tube prolonged beyond the ovary ; land plants. 



'Stamens all of equal length. 



Alternate stamens longer. 



1. ISNARDIA L. 



1. Is nor did. 



2. Raimannia. 



3. Hartmannia. 



Succulent herbs, mostly glabrous, aquatic or uliginous. Stems creeping 

 or floating; leaves opposite, relatively few, petiolecl. Flowers axillary, not 

 yellow. Calyx-segments 4, shorter than the tube or slightly longer. Petals 

 4, small, or wanting. Filaments very short. Ovary very short; styles often 

 almost wanting. Capsule obovoid or turbinate, straight. [In honor of Antoine 

 Dante Isnard, a French botanist, and a member of the Academy of Sciences, 

 died 1724.] About 4 species in Europe, Asia, continental North America, 

 Mexico and the West Indies. Type species: Isnardia palustris L. 



Fruit l*"-2" long. 

 Fruit 3"-4" long. 



1. I. palustris. 



2. I. repens. 



1. Isnardia palustris L. 



MARSH PURSLANE. (Fig. 

 286.) Stems branching, 4'- 

 20' long. Leaves oval, ovate 

 or spatulate, 6"-12" long, 

 narrowed into slender peti- 

 oles ; flowers solitary, about 

 1" broad ; bractlets at base 

 of the calyx usually none; 

 calyx-lobes triangular, acute ; 

 petals small, reddish, or 

 often wanting; capsule 4- 

 sided, slightly longer than 

 wide, about li" high, slightly 

 or somewhat exceeding the 

 calyx lobes. [Ludwigia 

 palustris Ell.] 



Pembroke Marsh, 1905. 

 Native. North temperate zone 

 and Santo Domingo. Flowers 

 from spring to autumn. Its 

 seeds were, presumably, trans- 

 ported to Bermuda by a bird. 



