120 DICOTYLEDONOUS PLANTS. 



under side ; peduncles axillary, 1 -flowered ; capsules obovate-globose, 

 4-angled, winged ; segments of the calyx large, ovate. Ludwigia. al- 

 temifolia Linn.L. macrocarpa Mich. 



HAB. Swamps. Can. to Flor. July. It. Stem 2 to 3 feet high. 

 Flowers yellow, on short peduncles. 



2. 7. uniflora Beck : stem straight, simple ; leaves alternate, lanceolate, 

 acute, smooth ; flower terminal ; petals longer than the calyx. Lud~ 

 tcigia ttniflora Raf. Torr. 



HAB. N. Jersey. This seems to be sufficiently distinct. Dr. 

 Torrey, however, suggests that it is a variety of the former. 



.3 /. hirsuta R. Sp S. : stem erect, sparingly branched, hairy ; leaves 

 alternate, oblong, sessile, somewhat hirsute ; peduncles 1 -flowered, 

 axillary; capsules globose, 4-angled, winged, hairy. Ludwigia pilosa 

 Walt. L. hirsuta Lam. 



HAB. Ditches and pools. July, Aug. !(. Stem 2 feet high. 

 Flowers yellow, axillary. 



** Petals none, ISNARDIA. 



4. /. palustris Linn. : stem prostrate, creeping, glabrous ; leaves op- 

 posite, ovate-lanceolate, tapering at base, petioled, smooth ; flowers 

 axillary, solitary, sessile ; capsule subovate, slightly angled. Ludtci- 

 gianitida Mich. Pursh. L. palustris EU. L. apetala WaU. 



HAB. Stagnant waters. Throughout the U. S. June. 1(. 

 Stem succulent. Flowers solitary, axillary, sessile. Corol none. 



ORDER XLII. CIRCJEACEjE. Lind. 



Calyx superior, deciduous, tubular, with a two parted limb. 

 Petals 2, alternate with the lobes of the calyx. Stamens 2, 

 alternate with the petals, inserted into the calyx. Disk large, 

 cup-shaped, filling up the whole of the tube of the calyx and 

 projecting beyond it. Ovary 2-celled ; style simple ; stigma 

 emarginate. Fruit 2-celled, 2-valved, 2-seeded. Seed sol- 

 itary, erect ; albumen none ; embryo erect ; radicle short. 



Herbs with opposite toothed and petioled haves. Flowers 

 in terminal and lateral racemes, covered with uncinate hairs. 



1. CIRC^A. Linn. 



Calyx short ; limb bipartite. Petals 2, obcordate. Sta- 

 mens 2, alternating with the petals. Stigma emarginate. 

 Capsule ovate, hispid, with uncinate hairs, 2-celled, 2-valved, 

 2-seeded. Diandria. Monogynia. 



1. C. lutetiana var. canadensis Linn. : stem erect ; leaves petioled, 

 ovate, remotely toothed, opaque, nearly smooth. C. canadensis Muhl. 

 C. lutetiana Big. 



