146 PRACTICAL BOTANY. 



and inserted, with the stamens, on the stalk of the ovary. 



Stem swollen at the joints. Leaves opposite or in whorls 



of 4. Silene, 



Calyx not tubular 198 



198. Stamens 9, rarely more, united in 3 sets, which are 

 separated by as many glands. Pod 3-celled. Flowers flesh- 

 color, in the axils of the leaves. Perennials, in marshes or 

 shallow water. Elodea. 



Stamens not in sets, and without intervening 

 glands 199 



199. Three parietal placentae in the 1-celled ovary. 

 Stamens 6-1 2, very rarely more, distinct or obscurely clus- 

 tered. Petals oblong or Unear, small. Sepals narrow, erect. 

 Annuals. Branches 4-angled. Leaves ovate, oblong, or lance- 

 linear, or awl-shaped, usually 1- to 5-nerved. 



Hypericum (in 4 spec.) 



A central or basilar placenta. Stems more or less swollen 

 at the joints. Ovary 1-celled, or, in one case, imperfectly 3- 

 to 5-celled 200 



300. Petals 2-cleft or parted. Stamens usually 10, rarely 

 fewer. (180) SteUaria (692). 



Petals entire or only slightly emarginate 201 



301. Stipules present, membranaceous, cleft. Styles 3, 

 rarely 5. Stamens 2 to 10. Sepals lanceolate, with scarious 

 edges. Leaves iiliforra-linear, slightly mucronate. Flowers 

 small, rose-color, on hairy pedicels. 



Spergularia rubra, Pers. 

 Stipules none 202 



303. Valves of the capsule 3, each 2-toothed. Styles 3..203 

 Valves of the capsule entii-e 204 



303. Seeds appendiculate at the hilum (strophiolate). 

 The white petals more than twice as long as the sepals. 



Moehringia lateriflora, L. 



Seeds not appendiculate. The white petals much 

 shorter than tlie hairy, 3-nerved sepals. 



Arenaria serpyllifolia, L 



