658 ORDER 126. CERATOPHYLLACEJ2. 



oblong-ovoid ; stigmas 2, sessile recurved ; capsule 2-celled ; seeds 

 minute. Small, submersed herbs, adhering to stones and pebbles. 



P. ceratoph^llum MX. Lvs. dichotomously dissected ; fls. solitary, axillary. 

 Mid. W. and S. States, in shallow streams. St. a few inches long, usually desti- 

 tute of roots and attached to stones by lateral, fleshy processes. Lvs. numerous, 

 olive-green, alternate, coriaceous, divided into many long, linear-setaceous seg- 

 ments. Fls. on short, thick peduncles, the 2 stamens and styles at length burst- 

 ing through the lacerated calyx. Jl. (Lacis ceratophylla Bougard.) 



ORDER CXXVI. CERATOPHYLLACE^E. HORNWORTS. 



Herbs aquatic, with verticillate, dichotomously dissected leaves. Flowers mo- 

 noecious, sessile, axillary, minute, with neither corolla nor calyx. Involucre 8 to 12- 

 cleft. $ Anthers (12 to 24) sessile. $ A simple, 1-celled ovary. Seed suspended, 

 orthotropous, embryo with 2 pairs of cotyledons, 



Genus 1 only, with 6? species, in the streams and pools of the northern hemisphere. 

 Properties Unimportant 



CERATOPHYL'LUM, L. HORNWORT. (Gr. Kt'pa?, a horn, 

 a leaf; alluding to the horn-like divisions of the leaves.) Character 

 the same as that of the Order. 



C. demersum L. LVB. 6 to 8 in a whorl, doubly dichotomous, dentate-spmes- 

 csnt on the back ; fls. axillary ; fr. 3-spined. 2{ An aquatic weed in ditches, etc., 

 -K Y. to Va., "W. to 111. St. floating or prostrate, 8 to 16' long, filiform, with 

 numerous whorls of leave?. These are dichotomously divided into- 2 or more 

 narrow, stiff segments. Fls. minute, axillary, sessile, with sessile anthers. Fr. 

 an oblong, beaked capsule, with 1 seed. Jl. Sept. 



FIG. C92. Tuxus Canadfcnsis-naked aecds. 



