LOOSESTRIFE TRIBE 



97 



Natural Order XXVII 



CERATOPHYLLACE^. The Horn-wort Tribe 



Stamens and pistils in separate flowers, but on the same plani 

 (monoecious) ; calyx many-parted ; corolla none ; stamens 10-20, 

 without filaments ; anthers 2-pointed ; ovary i-celled ; style 

 curved ; seed-vessel nut-like, i-seeded, not opening. In the present 

 volume the original arrangement of the earlier editions of the book 

 has been kept, viz. Ceratophyllacece contains but one genus, the 

 Horn-worts, and follows the Mare's-tail Tribe. Some botanists 

 place the Horn-worts and Water Spear-worts, as two genera forming 

 one Order, after the Spurges ; others place Water Star-wort among 

 the Mare's-tail Tribe, and Horn-wort as an Order by itself, following 

 the Spurges. The Horn-worts are an unim- 

 portant family of aquatic plants, very distinct 

 in structure from any other known plants, 

 with rigid whorled leaves, which are repeatedly 

 forked, and inconspicuous flowers. (Name in 

 Greek, signifying horn-leaved.) 



1. C. demcrsum (Common Horn-wort). 

 Fruit armed with 2 thorns near the base, and 

 terminated by the curved style. An aquatic 

 plant growing entirely under water, with long, 

 slender stems ; whorled, bristle - like leaves, 

 which are 2-4 times forked, and often in- 

 flated and jointed ; the flowers also are whorled, 

 and grow in the axils of the leaves. Slow 

 streams and ditches; frequent. Fl. July. 

 Perennial. 



C. submersum scarcely differs from the pre- 

 ceding, except in having fruit without thorns ; 

 and the plant is a paler green. 



Ceratophyllum 



Demersum (Common 



Horn-wort, 



Natural Order XXVIII 



LYTHRACEyE. Loosestrife Tribe 



Calyx tubular, many-parted, often with intermediate teeth ; 

 petals inserted between the outer divisions of the calyx, soon 

 falling off ; stamens springing from the tube of the calyx, within 

 the petals, and either equalling them in number, or twice, thrice, 

 or four times as many ; ovary 2 to 4-celled ; style single ; capsule 

 many-seeded, covered by the calyx, but not united to it. A large 

 Order containing both herbaceous and shrubby species, and repre- 

 sented in most parts of the Old and New World. Known by the 



