114 LYTHRACEiE. 



phoiis. Ovary 2 — 3- celled; styles or stigmas 2 or 3, acute and 



sessile. Fruit capsular, slightly pedicellate. Seeds numerous, 



minute, without albumen. — Herbaceous plants, with alternate 



leaves, which are usually cut into capillary segments. Flowers 



minute. 



PODOSTEMUM. Mich.— Vodostemum. 



(From the Greek novs iroSog, a foot, and jrj/juo;/, a stamen ; the stamens being 

 supported on a common footstalk.) 



Calyx and corolla none. Stamens 2, affixed to a common 

 pedicel. Stigmas 2, sessile, recurved. Capsule 2-celled, 2- 

 valved, many-seeded. 



P. ceratophyllum Mich. : leaves dichotomously many-parted ; peduncles 

 solitary, axillary. 



Rocks in streams. N. Y. to Ala. July, Aug. 0. IStem creeping, 1-^ 

 inches long, smooth, branching. Leaves alternate, crowded above. Flowers 

 axillary, on short fleshy peduncles. Horn-leaved Podostemum. 



. Order XLYI. CERATOPHYLLACE^.— Hornworts. 



Flowers monoecious. Calyx inferior, many-parted. Sterile 

 Fl. Stamens 12 — 20; filaments wanting; anthers 2-celled. 

 Fertile Fl. Ovary 1 -celled ; stigma filiform, oblique. Fruit 

 a beaked achenium. Seed pendulous, without albumen. — 

 Floating herbs, with dichotomous cellular verticillate leaves. 

 Flowers small. 



CERATOPHYLLUM. Linn.— Uomwort. 



(Ftom the Greek icfpaj, a /torn, and (pvWov, a.leaf; the dichotomous leaves 

 resembling horns.) 



Character same as of the order. 



C. echinatum Gray : achenium elliptic, slightly compressed, with 3 short 

 spines ; sides strongly muricated ; margins slightly winged, not gibbous, 

 armed with blunt teeth which finally become weak spines or horns as long 

 as the lateral spines. ( Torr. d^ Gr.) C. demersum (wholly or in part) of 

 American botanists. 



Ponds and slow-flowing streams. N. Y. to Virg. June, July. %. — Stem 

 submerged, branching, filiform, jointed. Leaves in numerous whorls of 6 — 8, 

 2 or 3-chotomously divided, the segments capillary. Flowers axillary, soUtary, 

 sessile, very minute. Rough Homwort. 



Order XLYII. LYTHRACE^.— Loosestrifes. 



Sepals combined into a 4 — V -toothed calyx, the sinuses some- 

 times lengthened into other teeth or processes. Petals inserted 

 between the teeth of the calyx, sometimes wanting. Stamens 



