POLYPETALOUS EXOGEKOUS PLANTS. 271 



the summit of the brunches, white; petals none; capsule 

 cubic-obconical, with concave sides and winged angles, as 

 long as the 6"rt/^a;-lobes ; seeds ovoid. Stem 2°-o° high. 



L. MICROCARPA, Miclix. Smootli ; ste?n low, creeping at 

 the base, 3-angled, mostly simple ; leaves spatulate-obovate, 

 petals none; capsule minute, cubic-obconical, shorter than 

 the cahjx-]oh(iS. Stem 6-12' high; capsule scarcely larger 

 than a pin's head. 



*♦♦ stems a'eeping ; leaves opposite. 

 t Petals none. 



L. PALUSTRis, Ell. Smooth; stems diffuse; leaves oho- 

 vate, tapering into a long petiole; capsule oblong or 

 obconical, obscurely 4-sided, longer than the cahjx-\ohQ^. 

 Stems G -12' long. 



L. SPATHULATA, Torr. and Gray. Pubescent and some- 

 what hoary ; leaves spatulate-obovate ; capsule ovoid. 



tt Petals 4. 



L. NATAXS, Ell. Smooth ; stems diffuse ; leaves obovate, 

 acutish, tapering into a long petiole; flowers short-pedi- 

 celed; jjetals roundish, as long as the lobes of the calyx; 

 capsule obtusely -i-angled, narrowed at the base. 



PROSERPmACA, L. 



Calyx-iv^^e 3-sided, 3-lobed; petals none; stamens 3; 

 stigmas 3; fruit bony, 3-angled, 3-celled, 3-seeded. — Herbs, 

 with pinnately dissected leaves, and minute axillary green- 

 ish ^o?i;e?\s. 



P. PALUSTRis, L. Leaves lanceolate, sharply serrate, the 

 submerged ones pectinate; stem l°-2|-° long, ascending or 

 floating. 



